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  <p>


            <a href="https://www.w3.org/"><img src="https://www.w3.org/Icons/w3c_home" alt="W3C" height="48" width="72"></a>


  </p>
  <h1 class="title p-name" id="title" property="dcterms:title">UI Events (formerly DOM Level 3 Events)</h1>

  <h2 id="w3c-working-draft-28-april-2015"><abbr title="World Wide Web Consortium">W3C</abbr> Working Draft <time property="dcterms:issued" class="dt-published" datetime="2015-04-28">28 April 2015</time></h2>
  <dl>

      <dt>This version:</dt>
      <dd><a class="u-url" href="http://www.w3.org/TR/2015/WD-uievents-20150428/">http://www.w3.org/TR/2015/WD-uievents-20150428/</a></dd>
      <dt>Latest published version:</dt>
      <dd><a href="http://www.w3.org/TR/uievents/">http://www.w3.org/TR/uievents/</a></dd>


      <dt>Latest editor's draft:</dt>
      <dd><a href="https://w3c.github.io/uievents/">https://w3c.github.io/uievents/</a></dd>


      <dt>Previous version:</dt>
      <dd><a rel="dcterms:replaces" href="http://www.w3.org/TR/2015/WD-uievents-20150319/">http://www.w3.org/TR/2015/WD-uievents-20150319/</a></dd>


    <dt>Editors:</dt>
    <dd class="p-author h-card vcard" property="bibo:editor" resource="_:editor0"><span property="rdf:first" typeof="foaf:Person"><meta property="foaf:name" content="Gary Kacmarcik"><a class="u-url url p-name fn" property="foaf:homepage" href="mailto:garykac@google.com?subject=%5BUI-events%5D%20Spec%20Feedback">Gary Kacmarcik</a>, <a property="foaf:workplaceHomepage" class="p-org org h-org h-card" href="http://www.google.com">Google, Inc.</a> (since Jun 2013)</span>
<span property="rdf:rest" resource="_:editor1"></span>
</dd>
<dd class="p-author h-card vcard" resource="_:editor1"><span property="rdf:first" typeof="foaf:Person"><meta property="foaf:name" content="Travis Leithead"><a class="u-url url p-name fn" property="foaf:homepage" href="mailto:travis.leithead@microsoft.com?subject=%5BUI-events%5D%20Spec%20Feedback">Travis Leithead</a>, <a property="foaf:workplaceHomepage" class="p-org org h-org h-card" href="http://www.microsoft.com">Microsoft Corp.</a> (since Feb 2012)</span>
<span property="rdf:rest" resource="rdf:nil"></span>
</dd>


          <dt>Participate:</dt>


                  <dd>
                    <a href="https://www.w3.org/Bugs/Public/enter_bug.cgi?component=DOM3%20Events&amp;product=WebAppsWG">
                      File a bug
                    </a>
                  </dd>


                  <dd>
                    <a href="https://www.w3.org/Bugs/Public/buglist.cgi?component=UI%20Events&amp;list_id=55051&amp;product=WebAppsWG&amp;resolution=---">
                      Bug list
                    </a>
                  </dd>


                  <dd>
                    <a href="http://lists.w3.org/Archives/Public/www-dom/">
                      Mailing list archive (www-dom)
                    </a>
                  </dd>


                  <dd>
                    <a href="https://github.com/w3c/uievents">
                      Github repository
                    </a>
                  </dd>


                  <dd>
                    <a href="https://github.com/w3c/uievents/commits">
                      Commit history
                    </a>
                  </dd>


                  <dd>
                    <a href="http://www.w3.org/2008/webapps/wiki/DOM3Events">
                      UI Events Wiki Home
                    </a>
                  </dd>


  </dl>


      <p class="copyright">
        <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> ©
        2015

        <a href="http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup>
        (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>,
        <a href="http://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>,
        <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>).

        <abbr title="World Wide Web Consortium">W3C</abbr> <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
        <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and

          <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a>

        rules apply.
      </p>


  <hr>
</div>
  <!-- Section: Abstract ========================================================-->
  <section property="dc:abstract" class="introductory" id="abstract"><h2 resource="#h-abstract" id="h-abstract"><span property="xhv:role" resource="xhv:heading">Abstract</span></h2>
    <p>This specification defines UI Events which extend the DOM Event objects defined in
        [<a href="#references-DOM4">DOM4</a>]. UI Events are those typically implemented by
            visual user agents for handling user interaction such as mouse and keyboard input.
      </p>
  </section><section id="sotd" class="introductory"><h2 resource="#h-sotd" id="h-sotd"><span property="xhv:role" resource="xhv:heading">Status of This Document</span></h2>


        <p>
          <em>This section describes the status of this document at the time of its publication.
          Other documents may supersede this document. A list of current <abbr title="World Wide Web Consortium">W3C</abbr> publications and the
          latest revision of this technical report can be found in the <a href="http://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> technical reports index</a> at
          http://www.w3.org/TR/.</em>
        </p>

    <p id="unstable">
      <strong class="redNote">Implementers should be aware that this document is not stable.</strong>
      Implementers who are not taking part in the discussions are likely to find the
      specification changing out from under them in incompatible ways.
      Vendors interested in implementing this document before it eventually reaches
      the Candidate Recommendation stage should join the aforementioned mailing lists
      and take part in the discussions.
      </p>

      <p>
        <strong class="redNote">The previous version of the <a href='http://www.w3.org/TR/2014/WD-uievents-20140612/'>UI Events specification</a> was extending DOM Level 3 Events but has been abandoned for now, due to the lack of time to work out the details of '<code><a href="http://www.w3.org/TR/2014/WD-uievents-20140612/#widl-KeyboardEvent-locale">locale</a></code>'</strong>. Future extensions may also be subsumed by additional work and proposals around the <a href="https://docs.google.com/document/d/1WLadG2dn4vlCewOmUtUEoRsThiptC7Ox28CRmYUn8Uw/edit">InputDevice API</a>, allowing access to information related to the physical device responsible for an event.
      </p>


        <p>
          This document was published by the <a href="http://www.w3.org/2008/webapps/">Web Applications Working Group</a> as a Working Draft.

            This document is intended to become a <abbr title="World Wide Web Consortium">W3C</abbr> Recommendation.


            If you wish to make comments regarding this document, please send them to
            <a href="mailto:www-dom@w3.org">www-dom@w3.org</a>
            (<a href="mailto:www-dom-request@w3.org?subject=subscribe">subscribe</a>,
            <a href="http://lists.w3.org/Archives/Public/www-dom/">archives</a>).
            All comments are welcome.
        </p>

          <p>
            Publication as a Working Draft does not imply endorsement by the <abbr title="World Wide Web Consortium">W3C</abbr>
            Membership. This is a draft document and may be updated, replaced or obsoleted by other
            documents at any time. It is inappropriate to cite this document as other than work in
            progress.
          </p>

        <p>
            This document was produced by a group operating under the
            <a id="sotd_patent" property="w3p:patentRules" href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <abbr title="World Wide Web Consortium">W3C</abbr> Patent
            Policy</a>.
              <abbr title="World Wide Web Consortium">W3C</abbr> maintains a <a href="http://www.w3.org/2004/01/pp-impl/42538/status" rel="disclosure">public list of any patent
              disclosures</a>
            made in connection with the deliverables of the group; that page also includes
            instructions for disclosing a patent. An individual who has actual knowledge of a patent
            which the individual believes contains
            <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
            Claim(s)</a> must disclose the information in accordance with
            <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
            6 of the <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
        </p>

          <p>This document is governed by the <a id="w3c_process_revision" href="http://www.w3.org/2014/Process-20140801/">1 August 2014 <abbr title="World Wide Web Consortium">W3C</abbr> Process Document</a>.
          </p>

</section><section id="toc"><h2 resource="#h-toc" id="h-toc" class="introductory"><span property="xhv:role" resource="xhv:heading">Table of Contents</span></h2><ul id="respecContents" role="directory" class="toc"><li class="tocline"><a class="tocxref" href="#dom-events-intro"><span class="secno">1. </span>Introduction</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#dom-events-overview"><span class="secno">1.1 </span>Overview</a></li><li class="tocline"><a class="tocxref" href="#dom-events-conformance"><span class="secno">1.2 </span>Conformance</a></li><li class="tocline"><a class="tocxref" href="#style-conventions"><span class="secno">1.3 </span>Stylistic Conventions</a></li></ul></li><li class="tocline"><a class="tocxref" href="#issues"><span class="secno">2. </span>Issues</a></li><li class="tocline"><a class="tocxref" href="#dom-event-architecture"><span class="secno">3. </span>DOM Event Architecture</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#event-flow"><span class="secno">3.1 </span>Event dispatch and DOM event flow</a></li><li class="tocline"><a class="tocxref" href="#event-flow-default-cancel"><span class="secno">3.2 </span>Default actions and cancelable events</a></li><li class="tocline"><a class="tocxref" href="#sync-async"><span class="secno">3.3 </span>Synchronous and asynchronous events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#event-order-and-loops"><span class="secno">3.3.1 </span>Event order and event loops</a></li></ul></li><li class="tocline"><a class="tocxref" href="#trusted-events"><span class="secno">3.4 </span>Trusted events</a></li><li class="tocline"><a class="tocxref" href="#event-flow-activation"><span class="secno">3.5 </span>Activation triggers and behavior</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#click-synthesis"><span class="secno">3.5.1 </span>Activation event synthesis</a></li><li class="tocline"><a class="tocxref" href="#events-activation-event-order"><span class="secno">3.5.2 </span>Activation event order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#event-exceptions"><span class="secno">3.6 </span>Event exceptions</a></li><li class="tocline"><a class="tocxref" href="#event-constructors"><span class="secno">3.7 </span>Constructing Mouse and Keyboard Events</a></li></ul></li><li class="tocline"><a class="tocxref" href="#event-interfaces"><span class="secno">4. </span>Basic Event Interfaces</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#event-types-list"><span class="secno">4.1 </span>List of Event Types</a></li></ul></li><li class="tocline"><a class="tocxref" href="#event-types"><span class="secno">5. </span>Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#events-uievents"><span class="secno">5.1 </span>User Interface Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-UIEvent"><span class="secno">5.1.1 </span>Interface UIEvent</a><ul class="toc"></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#events-focusevent"><span class="secno">5.2 </span>Focus Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-FocusEvent"><span class="secno">5.2.1 </span>Interface FocusEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#events-focusevent-event-order"><span class="secno">5.2.2 </span>Focus Event Order</a></li><li class="tocline"><a class="tocxref" href="#events-focusevent-doc-focus"><span class="secno">5.2.3 </span>Document Focus and Focus Context</a></li></ul></li><li class="tocline"><a class="tocxref" href="#events-mouseevents"><span class="secno">5.3 </span>Mouse Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-MouseEvent"><span class="secno">5.3.1 </span>Interface MouseEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#event-modifier-initializers"><span class="secno">5.3.2 </span>Event Modifier Initializers</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#events-mouseevent-event-order"><span class="secno">5.3.3 </span>Mouse Event Order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#events-wheelevents"><span class="secno">5.4 </span>Wheel Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-WheelEvent"><span class="secno">5.4.1 </span>Interface WheelEvent</a><ul class="toc"></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#events-keyboardevents"><span class="secno">5.5 </span>Keyboard Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-KeyboardEvent"><span class="secno">5.5.1 </span>Interface KeyboardEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#events-keyboard-event-order"><span class="secno">5.5.2 </span>Keyboard Event Order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#events-compositionevents"><span class="secno">5.6 </span>Composition Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-CompositionEvent"><span class="secno">5.6.1 </span>Interface CompositionEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#events-composition-event-order"><span class="secno">5.6.2 </span>Composition Event Order</a></li><li class="tocline"><a class="tocxref" href="#handwriting"><span class="secno">5.6.3 </span>Handwriting Recognition Systems</a></li><li class="tocline"><a class="tocxref" href="#events-composition-event-canceling"><span class="secno">5.6.4 </span>Canceling Composition Events</a></li><li class="tocline"><a class="tocxref" href="#events-composition-event-key-events"><span class="secno">5.6.5 </span>Key Events During Composition</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#events-composition-event-types"><span class="secno">5.6.6 </span>Composition Event Types</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#keys"><span class="secno">6. </span>Keyboard events and key values</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#keyboard-input"><span class="secno">6.1 </span>Keyboard Input</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#key-legends"><span class="secno">6.1.1 </span>Key Legends</a></li></ul></li><li class="tocline"><a class="tocxref" href="#keys-codevalues"><span class="secno">6.2 </span>Key codes</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#code-motivation"><span class="secno">6.2.1 </span>Motivation for Adding the <code>code</code> Attribute</a></li><li class="tocline"><a class="tocxref" href="#relationship-between-key-code"><span class="secno">6.2.2 </span>The Relationship Between <code>key</code> and <code>code</code></a></li><li class="tocline"><a class="tocxref" href="#code-examples"><span class="secno">6.2.3 </span><code>code</code> Examples</a></li><li class="tocline"><a class="tocxref" href="#code-virtual-keyboards"><span class="secno">6.2.4 </span><code>code</code> and Virtual Keyboards</a></li></ul></li><li class="tocline"><a class="tocxref" href="#keys-keyvalues"><span class="secno">6.3 </span>Keyboard Event <code>key</code> Values</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#keys-unicode"><span class="secno">6.3.1 </span>Key Values and Unicode</a></li><li class="tocline"><a class="tocxref" href="#keys-modifiers"><span class="secno">6.3.2 </span>Modifier keys</a></li><li class="tocline"><a class="tocxref" href="#keys-dead"><span class="secno">6.3.3 </span>Dead keys</a></li><li class="tocline"><a class="tocxref" href="#keys-IME"><span class="secno">6.3.4 </span>Input Method Editors</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#keys-cancelable-keys"><span class="secno">6.3.5 </span>Default actions and cancelable keyboard events</a></li><li class="tocline"><a class="tocxref" href="#keys-guidelines"><span class="secno">6.3.6 </span>Guidelines for selecting key values</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-event-initializers"><span class="secno">A. </span>Legacy Event Initializers</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#legacy-event-initializer-interfaces"><span class="secno">A.1 </span>Legacy Event Initializer Interfaces</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#idl-interface-CustomEvent-initializers"><span class="secno">A.1.1 </span>Initializers for interface CustomEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-UIEvent-initializers"><span class="secno">A.1.2 </span>Initializers for interface UIEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-FocusEvent-initializers"><span class="secno">A.1.3 </span>Initializers for interface FocusEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-MouseEvent-initializers"><span class="secno">A.1.4 </span>Initializers for interface MouseEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-WheelEvent-initializers"><span class="secno">A.1.5 </span>Initializers for interface WheelEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-KeyboardEvent-initializers"><span class="secno">A.1.6 </span>Initializers for interface KeyboardEvent</a><ul class="toc"></ul></li><li class="tocline"><a class="tocxref" href="#idl-interface-CompositionEvent-initializers"><span class="secno">A.1.7 </span>Initializers for interface CompositionEvent</a><ul class="toc"></ul></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-key-attributes"><span class="secno">B. </span>Legacy Key Attributes</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#KeyboardEvent-supplemental-interface"><span class="secno">B.1 </span>Legacy <span class="formerLink"><code>KeyboardEvent</code></span> supplemental interface</a></li><li class="tocline"><a class="tocxref" href="#legacy-key-models"><span class="secno">B.2 </span>Legacy key models</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#determine-keydown-keyup-keyCode"><span class="secno">B.2.1 </span>How to determine <code class="attribute-name">keyCode</code> for <code>keydown</code> and <code>keyup</code> events</a></li><li class="tocline"><a class="tocxref" href="#determine-keypress-keyCode"><span class="secno">B.2.2 </span>How to determine <code class="attribute-name">keyCode</code> for <span class="formerLink"><code>keypress</code></span> events</a></li><li class="tocline"><a class="tocxref" href="#fixed-virtual-key-codes"><span class="secno">B.2.3 </span>Fixed virtual key codes</a></li><li class="tocline"><a class="tocxref" href="#optionally-fixed-virtual-key-codes"><span class="secno">B.2.4 </span>Optionally fixed virtual key codes</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-event-types"><span class="secno">C. </span>Legacy Event Types</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#legacy-uievent-events"><span class="secno">C.1 </span>Legacy <span class="formerLink"><code>UIEvent</code></span> events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#legacy-uievent-event-order"><span class="secno">C.1.1 </span>Activation event order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-focusevent-events"><span class="secno">C.2 </span>Legacy <span class="formerLink"><code>FocusEvent</code></span> events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#legacy-focusevent-event-order"><span class="secno">C.2.1 </span>Legacy FocusEvent event order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-keyboardevent-events"><span class="secno">C.3 </span>Legacy <span class="formerLink"><code>KeyboardEvent</code></span> events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#keypress-event-order"><span class="secno">C.3.1 </span><span class="formerLink"><code>keypress</code></span> event order</a></li></ul></li><li class="tocline"><a class="tocxref" href="#legacy-mutationevent-events"><span class="secno">C.4 </span>Legacy <span class="formerLink"><code>MutationEvent</code></span> events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#interface-MutationEvent"><span class="secno">C.4.1 </span>Interface MutationEvent</a><ul class="toc"></ul></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#extending-events"><span class="secno">D. </span>Extending Events</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#extending-events-intro"><span class="secno">D.1 </span>Introduction</a></li><li class="tocline"><a class="tocxref" href="#extending-events-Custom_Events"><span class="secno">D.2 </span>Custom Events</a></li><li class="tocline"><a class="tocxref" href="#extending-events-Impl_Extensions"><span class="secno">D.3 </span>Implementation-Specific Extensions</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#extending-events-prefixes"><span class="secno">D.3.1 </span>Known Implementation-Specific Prefixes</a></li></ul></li></ul></li><li class="tocline"><a class="tocxref" href="#security-considerations"><span class="secno">E. </span>Security Considerations</a></li><li class="tocline"><a class="tocxref" href="#changes-from-earlier-versions"><span class="secno">F. </span>Changes</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#changes-DOMEvents2to3Changes"><span class="secno">F.1 </span>Changes between DOM Level 2 Events and UI Events (formerly DOM Level 3 Events)</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#changes-DOMEvents2to3Changes-flow"><span class="secno">F.1.1 </span>Changes to DOM Level 2 event flow</a></li><li class="tocline"><a class="tocxref" href="#changes-DOMEvents2to3Changes-event-types"><span class="secno">F.1.2 </span>Changes to DOM Level 2 event types</a></li><li class="tocline"><a class="tocxref" href="#changes-DOMLevel2to3Changes"><span class="secno">F.1.3 </span>Changes to DOM Level 2 Events interfaces</a></li><li class="tocline"><a class="tocxref" href="#changes-DOMLevel3Addons"><span class="secno">F.1.4 </span>New Interfaces</a></li></ul></li><li class="tocline"><a class="tocxref" href="#changes-drafts"><span class="secno">F.2 </span>Changes between different drafts of UI Events (formerly DOM Level 3 Events)</a></li></ul></li><li class="tocline"><a class="tocxref" href="#acknowledgements-contributors"><span class="secno">G. </span>Acknowledgements</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#acknowledgements-Productions"><span class="secno">G.1 </span>Production Systems</a></li></ul></li><li class="tocline"><a class="tocxref" href="#glossary"><span class="secno">H. </span>Glossary</a></li><li class="tocline"><a class="tocxref" href="#references"><span class="secno">I. </span>References</a><ul class="toc"><li class="tocline"><a class="tocxref" href="#references-References-Normative"><span class="secno">I.1 </span>Normative References</a></li><li class="tocline"><a class="tocxref" href="#references-References-Informative"><span class="secno">I.2 </span>Informative References</a></li></ul></li></ul></section>  <!-- abstract -->

  <!-- Section: SOTD ========================================================-->
    <!-- sotd -->

  <!-- Section 1: UI Events Overview  ========================================================-->
  <section property="bibo:hasPart" resource="#dom-events-intro" typeof="bibo:Chapter" id="dom-events-intro">
    <!--OddPage--><h2 resource="#h-dom-events-intro" id="h-dom-events-intro"><span property="xhv:role" resource="xhv:heading"><span class="secno">1. </span>Introduction</span></h2>

    <section property="bibo:hasPart" resource="#dom-events-overview" typeof="bibo:Chapter" id="dom-events-overview">
      <h3 resource="#h-dom-events-overview" id="h-dom-events-overview"><span property="xhv:role" resource="xhv:heading"><span class="secno">1.1 </span>Overview</span></h3>
      <p>DOM Events is designed with two main goals. The first goal is the design of an <a class="def" href="#glossary-event">event</a> system which allows registration
        of event listeners and describes event flow through a tree structure. Additionally, the specification will provide standard modules of events for user interface
        control and document mutation notifications, including defined contextual information for each of these event modules.</p>

      <p>The second goal of DOM Events is to provide a common subset of the current event systems used in existing browsers. This is intended to foster interoperability
        of existing scripts and content. It is not expected that this goal will be met with full backwards compatibility. However, the specification attempts to achieve
        this when possible.</p>
    </section>  <!-- dom-events-overview -->

    <section property="bibo:hasPart" resource="#dom-events-conformance" typeof="bibo:Chapter" id="dom-events-conformance">
      <h3 resource="#h-dom-events-conformance" id="h-dom-events-conformance"><span property="xhv:role" resource="xhv:heading"><span class="secno">1.2 </span>Conformance</span></h3>
      <p><strong>This section is normative.</strong></p>

      <p>Within this specification, the key words <q><em title="MUST" class="rfc2119">MUST</em></q>, <q><em title="MUST NOT" class="rfc2119">MUST NOT</em></q>, <q><em title="REQUIRED" class="rfc2119">REQUIRED</em></q>,
        <q><em title="SHALL" class="rfc2119">SHALL</em></q>, <q><em title="SHALL NOT" class="rfc2119">SHALL NOT</em></q>, <q><em title="SHOULD" class="rfc2119">SHOULD</em></q>, <q><em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em></q>,
        <q><em title="RECOMMENDED" class="rfc2119">RECOMMENDED</em></q>, <q><em title="MAY" class="rfc2119">MAY</em></q>, and <q><em title="OPTIONAL" class="rfc2119">OPTIONAL</em></q> are to be interpreted as described in
        [<a href="#RFC2119">RFC2119</a>].</p>

      <p>This specification is to be understood in the context of the DOM Level 3 Core specification
        [<cite><a class="normative" href="#references-DOMCore">DOM3 Core</a></cite>] and the general
        considerations for DOM implementations apply.
        For example, handling of <a class="def" href="#glossary-namespaceURI">namespace URIs</a> is discussed in
        <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-Core/core.html#Namespaces-Considerations"><em>XML Namespaces</em></a>.
        For additional information about
        <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-Core/introduction.html#ID-Conformance"><em>conformance</em></a>,
        please see the DOM Level 3 Core specification
        [<cite><a class="normative" href="#references-DOMCore">DOM3 Core</a></cite>].
        A <a class="def" href="#glossary-user-agent">user agent</a> is not required to conform
        to the entirety of another specification in order to conform to this specification, but it <em title="MUST" class="rfc2119">MUST</em>
        conform to the specific parts of any other specification which are called out in this specification
        (e.g., a conforming UI Events <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> support
        the <code>DOMString</code> data type as defined in <a href="#references-WebIDL">Web IDL</a>, but need
        not support every method or data type defined in <a href="#references-WebIDL">Web IDL</a> in order to
        conform to UI Events).
        </p>

      <p>This specification defines several classes of conformance for different
        <a class="def" href="#glossary-user-agent">user agents</a>, specifications, and content authors:
        </p>
      <dl>
        <dt id="conf-interactive-ua">Web browsers and other dynamic or interactive
          <a class="def" href="#glossary-user-agent">user agents</a>
          </dt>
        <dd>
          <p>A dynamic or interactive <a class="def" href="#glossary-user-agent">user agent</a>, referred to
            here as a <q>browser</q> (be it a Web browser, AT (Accessibility Technology) application,
            or other similar program), conforms to UI Events if it supports:
            </p>
          <ul>
            <li>the Core module defined in
              [<cite><a class="normative" href="#references-DOMCore">DOM3 Core</a></cite>]
              </li>
            <li>the <a href="#event-flow">Event dispatch and DOM event flow</a> mechanism
              </li>
            <li>all the interfaces and events with their associated methods, attributes, and
              semantics defined in this specification with the exception of those marked as
              <a class="def" href="#glossary-deprecated">deprecated</a> (a conforming user
              agent <em title="MAY" class="rfc2119">MAY</em> implement the deprecated interfaces, events, or APIs for backwards
              compatibility, but is not required to do so in order to be conforming)
              </li>
            <li>the complete set of <code>key</code> and <code>code</code> values defined in
              [<a href="#references-D3E-key">DOM3 key Values</a>] and
              [<a href="#references-D3E-code">DOM3 code Values</a>]
              (subject to platform availability), and
              </li>
            <li>all other normative requirements defined in this specification.
              </li>
          </ul>
          <p>A conforming browser <em title="MUST" class="rfc2119">MUST</em> <a class="def" href="#glossary-dispatch">dispatch</a> events appropriate
            to the given <a href="#interface-EventTarget">EventTarget</a> when the conditions defined
            for that <a class="def" href="#glossary-event-type">event type</a> have been met.
            </p>

          <p>A browser conforms specifically to UI Events if it implements
            the interfaces and related <a class="def" href="#glossary-event-type">event types</a>
            specified in <a href="#event-types">Event Types</a>.
            </p>

          <p>A conforming browser <em title="MUST" class="rfc2119">MUST</em> support scripting, declarative interactivity, or some other means of
            detecting and dispatching events in the manner described by this specification, and <em title="MUST" class="rfc2119">MUST</em> support
            the APIs specified for that <a class="def" href="#glossary-event-type">event type</a>.
            </p>

          <p>In addition to meeting all other conformance criteria, a conforming browser <em title="MAY" class="rfc2119">MAY</em> implement
            features of this specification marked as
            <a class="def" href="#glossary-deprecated">deprecated</a>, for backwards compatibility with
            existing content, but such implementation is discouraged.
            </p>

          <p>A conforming browser <em title="MAY" class="rfc2119">MAY</em> also support features not found in this specification, but which use
            the <a href="#event-flow">Event dispatch and DOM event flow</a> mechanism, interfaces, events,
            or other features defined in this specification, and <em title="MAY" class="rfc2119">MAY</em> implement additional interfaces and
            <a class="def" href="#glossary-event-type">event types</a> appropriate to that implementation.
            Such features can be later standardized in future specifications.
            </p>

          <p>A browser which does not conform to all required portions of this specification <em title="MUST NOT" class="rfc2119">MUST NOT</em> claim
            conformance to UI Events.
            Such an implementation which does conform to portions of this specification <em title="MAY" class="rfc2119">MAY</em> claim
            conformance to those specific portions.
            </p>

          <p>A conforming browser <em title="MUST" class="rfc2119">MUST</em> also be a <i>conforming implementation</i> of the IDL fragments in this
            specification, as described in the Web IDL specification <a href="#references-WebIDL">[WEBIDL]</a>.
            </p>
        </dd>

        <dt id="conf-author-tools">Authoring tools</dt>
        <dd>
          <p>A content authoring tool conforms to UI Events if it produces content which uses the
            <a class="def" href="#glossary-event-type">event types</a> and
            <a href="#event-flow">Event dispatch and DOM event flow</a> model, consistent in a manner as
            defined in this specification.
            </p>
          <p>A content authoring tool <em title="MUST NOT" class="rfc2119">MUST NOT</em> claim conformance to UI Events for content it produces
            which uses features of this specification marked as
            <a class="def" href="#glossary-deprecated">deprecated</a> in this specification.
            </p>
          <p>A conforming content authoring tool <em title="SHOULD" class="rfc2119">SHOULD</em> provide to the content author a means to use all
            <a class="def" href="#glossary-event-type">event types</a> and interfaces appropriate to all
            <a class="def" href="#glossary-host-language">host languages</a> in the content document being
            produced.
            </p>
        </dd>

        <dt id="conf-authors">Content authors and content</dt>
        <dd>
          <p>A content author creates conforming UI Events content if that content uses the
            <a class="def" href="#glossary-event-type">event types</a> and
            <a href="#event-flow">Event dispatch and DOM event flow</a> model, consistent in a manner as
            defined in this specification.
            </p>
          <p>A content author <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em> use features of this specification marked as
            <a class="def" href="#glossary-deprecated">deprecated</a>, but <em title="SHOULD" class="rfc2119">SHOULD</em> rely instead upon
            replacement mechanisms defined in this specification and elsewhere.
            </p>
          <p>Conforming content <em title="MUST" class="rfc2119">MUST</em> use the semantics of the interfaces and
            <a class="def" href="#glossary-event-type">event types</a> as described in this specification.
            </p>

          <div class="note"><div id="h-note1" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
            Content authors are advised to follow best practices as described in
            <a href="http://www.w3.org/TR/WAI-WEBCONTENT/">accessibility</a> and
            <a href="http://www.w3.org/standards/techs/i18n">internationalization</a> guideline
            specifications.
            </p></div>
        </dd>

        <dt id="conf-specs">Specifications and host languages</dt>
        <dd>
          <p>A specification or <a class="def" href="#glossary-host-language">host language</a> conforms
            to UI Events if it references and uses the
            <a href="#event-flow">Event dispatch and DOM event flow</a> mechanism, interfaces, events,
            or other features defined in [<a href="#references-DOM4">DOM4</a>], and does not extend these
            features in incompatible ways.
            </p>
          <p>A specification or <a class="def" href="#glossary-host-language">host language</a> conforms
            specifically to UI Events if it references and uses the interfaces and
            related <a class="def" href="#glossary-event-type">event types</a> specified in
            <a href="#event-types">Event Types</a>.
            A conforming specification <em title="MAY" class="rfc2119">MAY</em> define additional interfaces and
            <a class="def" href="#glossary-event-type">event types</a> appropriate to that specification,
            or <em title="MAY" class="rfc2119">MAY</em> extend the UI Events interfaces and
            <a class="def" href="#glossary-event-type">event types</a> in a manner that does not contradict
            or conflict with the definitions of those interfaces and
            <a class="def" href="#glossary-event-type">event types</a> in this specification.
            </p>

          <p>Specifications or <a class="def" href="#glossary-host-language">host languages</a> which
            reference UI Events <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em> use or recommend features of this
            specification marked as <a class="def" href="#glossary-deprecated">deprecated</a>, but
            <em title="SHOULD" class="rfc2119">SHOULD</em> use or recommend the indicated replacement for that the feature (if available).
            </p>
        </dd>
      </dl>
    </section>  <!-- dom-events-conformance -->

    <section property="bibo:hasPart" resource="#style-conventions" typeof="bibo:Chapter" id="style-conventions">
      <h3 resource="#h-style-conventions" id="h-style-conventions"><span property="xhv:role" resource="xhv:heading"><span class="secno">1.3 </span>Stylistic Conventions</span></h3>
      <p>This specification follows the <a href="http://www.w3.org/People/Schepers/spec-conventions.html">Proposed <abbr title="World Wide Web Consortium">W3C</abbr> Specification
        Conventions</a>, with the following supplemental additions:</p>

      <dl>
        <dt>Key and character values</dt>
        <dd><ul>
          <li>Names of key values are shown as: <code title="Key Value" class="key">'='</code> (e.g., the value of
            <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>).
            </li>
          <li>Names of key codes are shown as: <code title="Code Value" class="code">'Equal'</code> (e.g., the value of
            <a href="#widl-KeyboardEvent-code"><code>KeyboardEvent.code</code></a>).
            </li>
          <li>Character values of keys are shown as: <code title="Character Value" class="char">'\u003d'</code> (e.g., the code point
            of the key value).
            </li>
          <li>Glyphs representing character values are shown as: <code title="Character Value Glyph" class="glyph">'='</code> (e.g., the
            <a href="#key-legends"><em>key cap</em></a> or font associated with a character value).
            </li>
        </ul></dd>
      </dl>

      <p>In addition, certain terms are used in this specification with particular meanings.  The term <q>implementation</q> applies to a browser, content authoring tool,
        or other <a class="def" href="#glossary-user-agent">user agent</a> that implements this specification, while a content author is a person who writes script or code
        that takes advantage of the interfaces, methods, attributes, events, and other features described in this specification in order to make Web applications, and a
        user is the person who uses those Web applications in an implementation.</p>
    </section>  <!-- style-conventions -->
  </section>  <!-- dom-events-intro -->

  <!-- Section 2: Issues ==============================================================-->
  <section property="bibo:hasPart" resource="#issues" typeof="bibo:Chapter" id="issues">
    <!--OddPage--><h2 resource="#h-issues" id="h-issues"><span property="xhv:role" resource="xhv:heading"><span class="secno">2. </span>Issues</span></h2>

    <div class="issue"><div id="h-issue1" role="heading" aria-level="3" class="issue-title"><span>Issue 1</span></div><p class="">Open issues in this specification are called out using this convention.</p></div>
  </section>

  <!-- Section 3: Architecture ========================================================-->
  <section property="bibo:hasPart" resource="#dom-event-architecture" typeof="bibo:Chapter" id="dom-event-architecture">
    <!--OddPage--><h2 resource="#h-dom-event-architecture" id="h-dom-event-architecture"><span property="xhv:role" resource="xhv:heading"><span class="secno">3. </span>DOM Event Architecture</span></h2>

    <p><em>This section is informative.</em></p>

    <section property="bibo:hasPart" resource="#event-flow" typeof="bibo:Chapter" id="event-flow">
      <h3 resource="#h-event-flow" id="h-event-flow"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.1 </span>Event dispatch and DOM event flow</span></h3>

      <p>This section defines the event <a class="def" href="#glossary-dispatch">dispatch</a> mechanism of the event model defined in this specification.
        Applications <em title="MAY" class="rfc2119">MAY</em> dispatch event objects using the <a href="#widl-EventTarget-dispatchEvent"><code>EventTarget.dispatchEvent()</code></a> method, and
        implementations <em title="MUST" class="rfc2119">MUST</em> dispatch event objects as if through this method. The behavior of this method depends on the <em>event flow</em>
        associated with the underlying object. An event flow describes how event objects <em>propagate</em> through a data structure. As an example, when an event object
        is dispatched to an element in an XML document, the object propagates through parts of the document, as determined by the DOM event flow which is defined at the
        end of this section.</p>

      <figure id="figure-dom-event-flow">
        <img src="eventflow.svg" alt="Graphical representation of an event dispatched in a DOM tree using the DOM event flow" height="560">
        <figcaption>Fig. <span class="figno">1</span> <span class="fig-title">Graphical representation of an event dispatched in a DOM tree using the DOM event flow</span></figcaption>
      </figure>

      <p>Event objects are dispatched to an <a class="def" href="#glossary-event-target">event target</a>. At the beginning
        of the dispatch, implementations <em title="MUST" class="rfc2119">MUST</em> first determine the event object's <a class="def" href="#glossary-propagation-path">propagation path</a>.</p>

      <p>The propagation path <em title="MUST" class="rfc2119">MUST</em> be an ordered list of <a class="def" href="#glossary-current-event-target">current event targets</a> through which
        the event object <em title="MUST" class="rfc2119">MUST</em> pass. For DOM implementations, the propagation path <em title="MUST" class="rfc2119">MUST</em> reflect the hierarchical tree
        structure of the document. The last item in the list <em title="MUST" class="rfc2119">MUST</em> be the <a class="def" href="#glossary-event-target">event target</a>. The
        preceding items in the list are referred to as the <em>target's ancestors</em>, and the immediately preceding item as the <em>target's parent</em>. Once determined, the
        propagation path <em title="MUST NOT" class="rfc2119">MUST NOT</em> be changed. For DOM implementations, this applies even if an element in the propagation path is moved within the
        DOM or removed from the DOM.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>In the DOM event flow, event listeners might change the position of the <a class="def" href="#glossary-event-target">
        event target</a> in the document while the event object is being dispatched. Such changes do not affect the propagation path.</p>
      </div>

      <p>Note that event listeners are not copied over when <code>Node</code> are copied using methods such as
        <code>Node.cloneNode</code> or <code>Range.cloneContents</code>
        [<cite><a class="informative" href="#references-DOMRange">DOM Range</a></cite>].
        </p>

      <p>Exceptions thrown inside event listeners <em title="MUST NOT" class="rfc2119">MUST NOT</em> stop the propagation of the event or affect the
        <a class="def" href="#glossary-propagation-path">propagation path</a>. The exception itself <em title="MUST NOT" class="rfc2119">MUST NOT</em> propagate outside the scope of the event
        handler.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>In the following code, the exception thrown from the call to <code>throw "Error"</code> does not propagate into the parent scope
        (which would prevent the <code>console.log</code> statement from executing):</p>
<pre>var e = document.createEvent("Event");
e.initEvent("myevent", false, false);
var target = document.createElement("div");
target.addEventListener("myevent", function () {
   throw "Error";
});
target.dispatchEvent(e); <span class="comment">// Causes the event listener to throw an exception...</span>
<span class="comment">// The previously thrown exception doesn't affect the code that follows:</span>
console.log("Exceptions? No problem");</pre>
      </div>

      <p id="event-phase">As the next step, the event object <em title="MUST" class="rfc2119">MUST</em> complete one or more <a class="def" href="#glossary-phase">event phases</a>. This specification defines
        three event phases: <a href="#capture-phase">capture phase</a>, <a href="#target-phase">target phase</a> and <a href="#bubble-phase">bubble phase</a>.  Event objects
        complete these phases in the specified order using the partial propagation paths as defined below. A phase <em title="MUST" class="rfc2119">MUST</em> be skipped if it is not
        supported, or if the event object's propagation has been stopped. For example, if the <a href="#widl-Event-bubbles"><code>Event.bubbles</code></a>
        attribute is set to false, the bubble phase will be skipped, and if <a href="#widl-Event-stopPropagation"><code>Event.stopPropagation()</code></a> has been
        called prior to the dispatch, all phases <em title="MUST" class="rfc2119">MUST</em> be skipped.</p>

      <ol>
        <li>The <strong id="capture-phase">capture phase</strong>: The event object <em title="MUST" class="rfc2119">MUST</em> propagate through the target's ancestors from the <a class="def" href="#glossary-window">Window</a> to the target's parent. This phase is also known as the <em>capturing phase</em>. Event
          listeners registered for this phase <em title="MUST" class="rfc2119">MUST</em> handle the event before it reaches its target.</li>

        <li>The <strong id="target-phase">target phase</strong>: The event object <em title="MUST" class="rfc2119">MUST</em> arrive at the event object's <a class="def" href="#glossary-event-target">
          event target</a>. This phase is also known as the <em>at-target phase</em>. Event listeners registered for this phase <em title="MUST" class="rfc2119">MUST</em>
          handle the event once it has reached its target. If the <a class="def" href="#glossary-event-type">event type</a> indicates that
          the event <em title="MUST NOT" class="rfc2119">MUST NOT</em> bubble, the event object <em title="MUST" class="rfc2119">MUST</em> halt after completion of this phase.</li>

        <li>The <strong id="bubble-phase">bubble phase</strong>: The event object propagates through the target's ancestors in reverse order, starting
          with the target's parent and ending with the <a class="def" href="#glossary-window">Window</a>. This phase is also known as the <em>bubbling phase</em>.
          Event listeners registered for this phase <em title="MUST" class="rfc2119">MUST</em> handle the event after it has reached its target.</li>
      </ol>

      <p>Implementations <em title="MUST" class="rfc2119">MUST</em> let event objects accomplish an event phase by applying the following steps while there are pending event targets in
        the partial propagation path for this phase and the event object's propagation has not been stopped through <a href="#widl-Event-stopPropagation"><code>
        Event.stopPropagation()</code></a>.</p>

      <p>First, the implementation <em title="MUST" class="rfc2119">MUST</em> determine the <em>current target</em>. This <em title="MUST" class="rfc2119">MUST</em> be the next pending event target in the partial propagation
        path, starting with the first. From the perspective of an event listener this <em title="MUST" class="rfc2119">MUST</em> be the event target the listener has been registered on.</p>

      <p>Next, the implementation <em title="MUST" class="rfc2119">MUST</em> determine the current target's <a class="def" href="#glossary-candidate-event-handlers">candidate event listeners</a>.
        This <em title="MUST" class="rfc2119">MUST</em> be the list of all event listeners that have been registered on the current target in their order of registration. [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>] defines the ordering of listeners registered through event handler attributes. Once determined, the candidate event listeners
        <em title="MUST NOT" class="rfc2119">MUST NOT</em> be changed. Adding or removing listeners does not affect the current target's candidate event listeners.</p>

      <p>Finally, the implementation <em title="MUST" class="rfc2119">MUST</em> process all candidate <a class="def" href="#glossary-event-handler">event handlers</a> in order and trigger
        each handler if all the following conditions are met:</p>

      <ul>
        <li>The event object's immediate propagation has not been stopped.</li>

        <li>The listener has been registered for this event phase.</li>

        <li>The listener has been registered for this <a class="def" href="#glossary-event-type">event type</a>.</li>
      </ul>

      <p>In the production of the <a class="def" href="#glossary-propagation-path">propagation path</a>, the event propagates from the <a class="def" href="#glossary-window">Window</a>
        to the <code>document</code> object during the <a class="def" href="#glossary-capture-phase">capture phase</a>, and from the <code>document</code> object to the
        <a class="def" href="#glossary-window">Window</a> during the <a class="def" href="#glossary-bubbling-phase">bubble phase</a>.</p>

      <p>After an event completes all the phases of its <a class="def" href="#glossary-propagation-path">propagation path</a>, its <a href="#widl-Event-currentTarget">
        <code>Event.currentTarget</code></a> <em title="MUST" class="rfc2119">MUST</em> be set to <code>null</code> and the <a href="#widl-Event-eventPhase"><code>Event.eventPhase</code></a> <em title="MUST" class="rfc2119">MUST</em> be
        set to <code>0</code> (<a href="#widl-Event-NONE"><code>NONE</code></a>). All other attributes of the <code>Event</code> (or interface derived from <code>Event</code>)
        are unchanged (including the <a href="#widl-Event-target"><code>Event.target</code></a> attribute, which <em title="MUST" class="rfc2119">MUST</em> continue to reference the <a class="def" href="#glossary-event-target">
        event target</a>).</p>

      <p>The model defined above <em title="MUST" class="rfc2119">MUST</em> be applied regardless of the specific event flow associated with an event target. Each event flow <em title="MUST" class="rfc2119">MUST</em> define how the propagation path
        <em title="MUST" class="rfc2119">MUST</em> be determined and which event phases are supported. The <em>DOM event flow</em> is an application of this model: the propagation path for a <code>Node</code>
        object <em title="MUST" class="rfc2119">MUST</em> be determined by its <code>Node.parentNode</code> chain, and if applicable, the document's containing <a class="def" href="#glossary-window">Window</a>.
        All events accomplish the capture and target phases. Whether an event accomplishes the bubble phase <em title="MUST" class="rfc2119">MUST</em> be defined individually for each <a class="def" href="#glossary-event-type">
        event type</a>. An alternate application of this model can be found in [<cite><a class="informative" href="#references-DOMLS">DOM3 Load and Save</a></cite>].</p>

      <p>Implementations of the DOM event model <em title="MUST" class="rfc2119">MUST</em> be reentrant. Event listeners <em title="MAY" class="rfc2119">MAY</em> perform actions that cause additional events to be dispatched. Such events are handled
        in a synchronous manner, the event propagation that causes the event listener to be triggered <em title="MUST" class="rfc2119">MUST</em> resume only after the event dispatch of the new event is completed.</p>

    </section>  <!-- event-flow -->

    <section property="bibo:hasPart" resource="#event-flow-default-cancel" typeof="bibo:Chapter" id="event-flow-default-cancel">
      <h3 resource="#h-event-flow-default-cancel" id="h-event-flow-default-cancel"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.2 </span>Default actions and cancelable events</span></h3>

      <p>Events are typically dispatched by the implementation as a result of a user action, in response to the completion of a task, or to signal progress during asynchronous
        activity (such as a network request). Some events can be used to control the behavior that the implementation <em title="MAY" class="rfc2119">MAY</em> take next (or undo an action that the implementation
        already took). Events in this category are said to be <em>cancelable</em> and the behavior they cancel is called their <a class="def" href="#glossary-default-action">
        <em>default action</em></a>. Cancelable event objects can be associated with one or more <a class="def" href="#glossary-default-action">default actions</a>.
        To cancel an event, call the <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a> method.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>A <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> event is dispatched immediately after the user presses down a button on a
        pointing device (typically a mouse). One possible <a class="def" href="#glossary-default-action">default action</a> taken by the implementation is to set up a state
        machine that allows the user to drag images or select text. The <a class="def" href="#glossary-default-action">default action</a> depends on what happens next — for
        example, if the user's pointing device is over text, a text selection might begin. If the user's pointing device is over an image, then an image-drag action could
        begin. Preventing the <a class="def" href="#glossary-default-action">default action</a> of a <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a>
        event prevents these actions from occuring.</p>
      </div>

      <p><a class="def" href="#glossary-default-action">Default actions</a> <em title="SHOULD" class="rfc2119">SHOULD</em> be performed after the event dispatch has been completed, but in exceptional
        cases <em title="MAY" class="rfc2119">MAY</em> also be performed immediately before the event is dispatched.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>The default action associated with the <a class="eventtype" href="#event-type-click"><code>click</code></a> event on <code>&lt;input
        type="checkbox"&gt;</code> elements toggles the <code>checked</code> IDL attribute value of that element. If the <a class="eventtype" href="#event-type-click"><code>click</code>
        </a> event's default action is cancelled, then the value is restored to its former state.</p>
      </div>

      <p id="events-dt-cancelable-event">When an event is canceled, then the conditional <a class="def" href="#glossary-default-action">default actions</a> associated with the event <em title="MUST" class="rfc2119">MUST</em> be skipped (or
        as mentioned above, if the <a class="def" href="#glossary-default-action">default actions</a> are carried out before the dispatch, their effect <em title="MUST" class="rfc2119">MUST</em> be undone).
        Whether an event object is cancelable <em title="MUST" class="rfc2119">MUST</em> be indicated by the <a href="#widl-Event-cancelable"><code>Event.cancelable</code></a> attribute. <a href="#widl-Event-preventDefault">
        <code>Event.preventDefault()</code></a> stops all related <a class="def" href="#glossary-default-action">default actions</a> of an event object. The <a href="#widl-Event-defaultPrevented">
        <code>Event.defaultPrevented</code></a> attribute indicates whether an event has already been canceled (e.g., by a prior event listener). If the <a class="def" href="#glossary-DOM-application">
        DOM application</a> itself initiated the dispatch, then the return value of the <a href="#widl-EventTarget-dispatchEvent"><code>EventTarget.dispatchEvent()</code></a>
        method indicates whether the event object was cancelled.</p>

      <div class="note"><div id="h-note2" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note: </strong>Many implementations additionally interpret an event listener's return value, such as the value <code>false</code>, to mean
        that the <a class="def" href="#glossary-default-action">default action</a> of cancelable events will be cancelled (though <code>window.onerror</code> handlers are cancelled
        by returning <code>true</code>).</p></div>

      <div class="note"><div id="h-note3" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note: </strong>Some cancelable events might not have any observable <a class="def" href="#glossary-default-action">default actions</a>. For
        example, the <a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a> event.</p></div>

      <p>This specification does not offer features to programatically query if an event object has any <a class="def" href="#glossary-default-action">default action</a> associated with
        it, or to associate new <a class="def" href="#glossary-default-action">default actions</a> with an event object. Other specifications <em title="SHOULD" class="rfc2119">SHOULD</em> define what default actions, if any,
        are associated with certain event objects. Further, implementations <em title="MAY" class="rfc2119">MAY</em> associate <a class="def" href="#glossary-default-action">default actions</a> with events as necessary and
        appropriate for that implementation.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>As an example, one implementation might scroll a document view by a certain amount as the <a class="def" href="#glossary-default-action">
        default action</a> of a <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event, while another implementation might instead zoom the document as its <a class="def" href="#glossary-default-action">default action</a>.</p>
      </div>
    </section>  <!-- event-flow-default-cancel -->

    <section property="bibo:hasPart" resource="#sync-async" typeof="bibo:Chapter" id="sync-async">
      <h3 resource="#h-sync-async" id="h-sync-async"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.3 </span>Synchronous and asynchronous events</span></h3>

      <p>Events <em title="MAY" class="rfc2119">MAY</em> be dispatched either synchronously or asynchronously.</p>

      <p>Events which are synchronous (<em><q>sync events</q></em>) <em title="MUST" class="rfc2119">MUST</em> be treated as if they are in a virtual queue in a first-in-first-out model, ordered by sequence
        of temporal occurrence with respect to other events, to changes in the DOM, and to user interaction.  Each event in this virtual queue <em title="MUST" class="rfc2119">MUST</em> be delayed until the
        previous event has completed its propagation behavior, or been canceled.  Some sync events are driven by a specific device or process, such as mouse button events.
        These events are governed by the <a class="def" href="#glossary-event-order">event order</a> algorithms defined for that set of events, and a user agent <em title="MUST" class="rfc2119">MUST</em> dispatch
        these events in the defined order.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>A user double-clicks a passage of text to select a word, then presses the <code title="Key Value" class="key">'Delete'</code>
        key to erase the word, triggering the following synchronous sequence of events:
          <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a>,
          <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>,
          <a class="eventtype" href="#event-type-click"><code>click</code></a>,
          <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a>,
          <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>,
          <a class="eventtype" href="#event-type-click"><code>click</code></a>,
          <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a>,
          <a class="eventtype" href="#event-type-select"><code>select</code></a>,
          <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>,
          <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>,
          <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>,
          <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>.
        Each of these events are fired in the sequence initiated by the user's actions.</p>
      </div>

      <p>Events which are asynchronous (<em><q>async events</q></em>) <em title="MAY" class="rfc2119">MAY</em> be dispatched as the results of the action are completed, with no relation to other events, to
        other changes in the DOM, nor to user interaction.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>During loading of a document, an inline script element is parsed and executed. The <a class="eventtype" href="#event-type-load">
        <code>load</code></a> event is queued to be fired asynchronously at the script element. However, because it is an async event, its order with relation to other synchronous
        events fired during document load (such as the <code class="eventtype">DOMContentLoaded</code> event from <cite><a class="informative" href="#references-HTML5">HTML5</a></cite>) is not guaranteed.</p>
      </div>

      <section property="bibo:hasPart" resource="#event-order-and-loops" typeof="bibo:Chapter" id="event-order-and-loops">
        <h4 resource="#h-event-order-and-loops" id="h-event-order-and-loops"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.3.1 </span>Event order and event loops</span></h4>

        <p>Most events take place in a sequential context.  [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>] defines its event operations in terms
          of an event loop mechanism, in which events of all types are fed into different <em>task queues</em>.  This specification does not define events in terms of this
          event loop mechanism, but it is compatible with this mechanism.  Instead, this specification defines several operation-specific <a class="def" href="#glossary-event-order">
          event orders</a>.</p>

        <p>Using the terminology of HTML5, each independent device, such as a mouse or keyboard, <em title="SHOULD" class="rfc2119">SHOULD</em> be treated as a <em>task source</em> which feeds into the appropriate
          <em>task queue</em>, in the order defined by the <a class="def" href="#glossary-event-order">event order</a> associated with that device. Each operation, such as
          a focus change or composition input, also acts as a <em>task source</em> for the appropriate <em>task queue</em>.  The resolution of these event loops is handled
          in a manner conforming to the <a class="def" href="#glossary-host-language">host language</a>, such as HTML [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>].</p>

        <div class="note"><div id="h-note4" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong> Certain events, such as <q>hotkeys</q> or control keys pressed in a certain sequence, can be
          <q>swallowed</q> by the operating system or the application, interrupting the expected <a class="def" href="#glossary-event-order">event order</a>.</p></div>
      </section>  <!-- event-order-and-loops -->
    </section>  <!-- sync-async -->

    <section property="bibo:hasPart" resource="#trusted-events" typeof="bibo:Chapter" id="trusted-events">
      <h3 resource="#h-trusted-events" id="h-trusted-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.4 </span>Trusted events</span></h3>

      <p>Events that are generated by the user agent, either as a result of user interaction, or as a direct result of changes to the DOM, are trusted by the user agent
        with privileges that are not afforded to events generated by script through the <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("Event")</code></a>
        method, modified using the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method, or dispatched via the <a href="#widl-EventTarget-dispatchEvent">
        <code>EventTarget.dispatchEvent()</code></a> method.  The <a href="#widl-Event-isTrusted"><code>isTrusted</code></a> attribute of trusted events has a
        value of <code>true</code>, while untrusted events have a <a href="#widl-Event-isTrusted"><code>isTrusted</code></a> attribute value of <code>false</code>.</p>

      <p>Most untrusted events <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em> trigger <a class="def" href="#glossary-default-action">default actions</a>, with the exception of the <a class="eventtype" href="#event-type-click">
        <code>click</code></a> event. This event always triggers the <a class="def" href="#glossary-default-action">
        default action</a>, even if the <a href="#widl-Event-isTrusted"><code>isTrusted</code></a> attribute is <code>false</code> (this behavior is retained for backward-compatibility).
        All other untrusted events <em title="MUST" class="rfc2119">MUST</em> behave
        as if the <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a> method had been called on that event.</p>
    </section>  <!-- trusted-events -->

    <section property="bibo:hasPart" resource="#event-flow-activation" typeof="bibo:Chapter" id="event-flow-activation">
      <h3 resource="#h-event-flow-activation" id="h-event-flow-activation"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.5 </span>Activation triggers and behavior</span></h3>

      <p>Certain <a class="def" href="#glossary-event-target">event targets</a> (such as a link or button element) <em title="MAY" class="rfc2119">MAY</em> have associated <a class="def" href="#glossary-activation-behavior">
        activation behavior</a> (such a following a link) that implementations perform in response to an <em><a class="def" href="#glossary-activation-trigger">activation
        trigger</a></em> (such as clicking a link).</p>

      <p>A <a class="def" href="#glossary-host-language">host language</a> <em title="SHOULD" class="rfc2119">SHOULD</em> indicate which, if any, elements have activation behavior, describe appropriate <a class="def" href="#glossary-activation-trigger">activation triggers</a>, and define the result of that activation behavior.  An implementation which supports a <a class="def" href="#glossary-host-language">host language</a> <em title="SHOULD" class="rfc2119">SHOULD</em> initiate these <a class="def" href="#glossary-activation-behavior">activation behavior</a> when the associated
        <a class="def" href="#glossary-activation-trigger">activation trigger</a> occurs.</p>

      <div class="example" id="example-activation">
        <div class="example-title"></div>
        <p>Both HTML and SVG have an <code>&lt;a&gt;</code> element which indicates a link.  Relevant <a class="def" href="#glossary-activation-trigger">activation triggers</a> for an <code>&lt;a&gt;</code> element are a <a class="eventtype" href="#event-type-click"><code>
        click</code></a> event on the text or image  content of the <code>&lt;a&gt;</code> element, or a <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
        event with a <a href="#widl-KeyboardEvent-key">key</a> attribute value of <code title="Key Value" class="key">'Enter'</code> key when the <code>&lt;a&gt;</code>
        element has focus.  The activation behavior for an <code>&lt;a&gt;</code> element is normally to change the content of the window to the content of the new document,
        in the case of external links, or to reposition the current document relative to the new anchor, in the case of internal links.</p>
      </div>

      <p>An <a class="def" href="#glossary-activation-trigger">activation trigger</a> is a user action or an event which indicates to the implementation that an activation
        behavior <em title="SHOULD" class="rfc2119">SHOULD</em> be initiated.  User-initiated <a class="def" href="#glossary-activation-trigger">activation triggers</a> include clicking a mouse button on an activatable
        element, pressing the <code title="Key Value" class="key">'Enter'</code> key when an activatable element has focus, or pressing a key that is somehow
        linked to an activatable element (a <q>hotkey</q> or <q>access key</q>) even when that element does not have focus.  Event-based <a class="def" href="#glossary-activation-trigger">
        activation triggers</a> <em title="MAY" class="rfc2119">MAY</em> include timer-based events that activate an element at a certain clock time or after a certain time period has elapsed, progress
        events after a certain action has been completed, or many other condition-based or state-based events.</p>

      <p>In some cases, a <a class="def" href="#glossary-host-language">host language</a> <em title="MAY" class="rfc2119">MAY</em> define attributes or even attribute values which add to or change the native
        <a class="def" href="#glossary-activation-trigger">activation trigger</a> or <a class="def" href="#glossary-activation-behavior">activation behavior</a> of an element.
        For example, ARIA [<cite><a class="informative" href="#ref-ARIA">ARIA</a></cite>] defines values for the <code class="attr">role</code> attribute that add semantics
        to the element to which it is applied, for purposes of enhanced accessibility.  In such cases, if the <a class="def" href="#glossary-host-language">host language</a>
        does not explicitly define the <a class="def" href="#glossary-activation-trigger">activation trigger</a> or <a class="def" href="#glossary-activation-behavior">activation
        behavior</a>, the content author <em title="MUST" class="rfc2119">MUST</em> provide the mechanics of the <a class="def" href="#glossary-activation-trigger">activation trigger</a> (via an event listener)
        or <a class="def" href="#glossary-activation-behavior">activation behavior</a> (such as calling an ECMAScript function) for that element when applying that attribute
        or attribute value.</p>

      <section property="bibo:hasPart" resource="#click-synthesis" typeof="bibo:Chapter" id="click-synthesis">
        <h4 resource="#h-click-synthesis" id="h-click-synthesis"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.5.1 </span>Activation event synthesis</span></h4>

        <p>If the instance of the <a class="def" href="#glossary-activation-trigger">activation trigger</a> is not an event of <a class="def" href="#glossary-event-type">event
          type</a> <a class="eventtype" href="#event-type-click"><code>click</code></a> (that is, when it does not result from a user's activation of a button or link
          using a mouse or equivalent pointing device), the implementation <em title="MUST" class="rfc2119">MUST</em> synthesize and dispatch an event of <a class="def" href="#glossary-event-type">event type</a> <a class="eventtype" href="#event-type-click"><code>click</code></a> as one of the <a class="def" href="#glossary-default-action">default actions</a> of that <a class="def" href="#glossary-activation-trigger">activation trigger</a>. The value of the <code class="attribute-name"><a href="#widl-Event-target">Event.target</a></code>
          <em title="MUST" class="rfc2119">MUST</em> be set to the <a class="def" href="#glossary-event-target">event target</a> (normally, the currently focused element), and the event <em title="MUST" class="rfc2119">MUST</em> simulate a <em>left
          click</em> (i.e., the <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a> attribute value <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>, and the <a href="#widl-MouseEvent-buttons">
          <code>MouseEvent.buttons</code></a> attribute value <em title="MUST" class="rfc2119">MUST</em> be <code>1</code>).  Other context information of such a simulated <a class="eventtype" href="#event-type-click">
          <code>click</code></a> event is implementation dependent, but for historical purposes, the interface for the <a class="eventtype" href="#event-type-click"><code>click</code></a>
          event <em title="MUST" class="rfc2119">MUST</em> be the <a href="#interface-MouseEvent"><code>MouseEvent interface</code></a>, regardless of the actual device used to activate the element.  Preventing
          the <a class="def" href="#glossary-default-action">default action</a> of the <a class="def" href="#glossary-activation-trigger">activation trigger</a>, such as
          with the <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>, <em title="MUST" class="rfc2119">MUST</em> stop the initiation of the <a class="def" href="#glossary-activation-behavior">
          activation behavior</a>.</p>

        <div class="example">
          <div class="example-title"></div>
          <p>When a user activates a hyperlink using a keyboard, such as by focusing the hyperlink element
          and pressing the <code title="Key Value" class="key">'Enter'</code> or <code title="Key Value" class="key">'&nbsp;'</code> key, a <a class="eventtype" href="#event-type-click"><code>click</code></a> event would be dispatched as the <a class="def" href="#glossary-default-action">default action</a> of the respective
          <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event.</p>
        </div>

        <p>Implementations <em title="MUST" class="rfc2119">MUST</em> dispatch the synthesized <a class="eventtype" href="#event-type-click"><code>click</code></a> event as described above even if they do not
          normally dispatch such an event (e.g., when activation is requested by a voice command, since this specification does not address <a class="def" href="#glossary-event-type">
          event types</a> for voice input).</p>

        <div class="note"><div id="h-note5" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The activation of an event target is device dependent, but is also application dependent, e.g., a link in a document can be activated
          using a mouse click or a mouse double click.</p></div>
      </section>  <!-- click-synthesis -->

      <section property="bibo:hasPart" resource="#events-activation-event-order" typeof="bibo:Chapter" id="events-activation-event-order">
        <h4 resource="#h-events-activation-event-order" id="h-events-activation-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.5.2 </span>Activation event order</span></h4>

        <p>Activation triggers and behavior can be defined in part by the events which are dispatched in a set order relative to one another.  The following is the typical
          sequence of events for an element activated by a pointing device (with only pertinent events listed):</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td>
              <em>All <a class="def" href="#glossary-default-action">default actions</a>,
              including the <a class="def" href="#glossary-activation-behavior">activation behavior</a></em>
            </td>
          </tr>
        </tbody></table>

        <p>The following is the typical sequence of events when a focused element is activated by a key event (with only pertinent events listed):</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td><em title="MUST" class="rfc2119">MUST</em> be a key which can activate the element, such as the
              <code title="Key Value" class="key">'Enter'</code> or <code title="Key Value" class="key">'&nbsp;'</code> key,
              or the element is not activated</td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td><a class="def" href="#glossary-default-action">default action</a>; synthesized; <code>isTrusted="true"</code></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td>
              <em>All <a class="def" href="#glossary-default-action">default actions</a>,
              including the <a class="def" href="#glossary-activation-behavior">activation behavior</a></em>
            </td>
          </tr>
        </tbody></table>
      </section>  <!-- events-activation-event-order -->
    </section>  <!-- event-flow-activation -->

    <section property="bibo:hasPart" resource="#event-exceptions" typeof="bibo:Chapter" id="event-exceptions">
      <h3 resource="#h-event-exceptions" id="h-event-exceptions"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.6 </span>Event exceptions</span></h3>

      <p><em>This section is informative.</em></p>

      <p>Event operations can throw a <code>DOMException</code> as specified in their method descriptions.</p>

      <div class="note"><div id="h-note6" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="note-eventexcpetion-removed"><strong>Note:</strong> The exception <em>EventException</em> introduced in <strong class="version">DOM Level 2</strong> is
        removed in this specification as part of this specification's normative support of <a href="#references-WebIDL">Web IDL</a>. <em>EventException</em> formerly defined
        an exception code <code>UNSPECIFIED_EVENT_TYPE_ERR</code> which is replaced in this specification by the use of a <code>DOMException</code> of type
        <code>InvalidStateError</code>.</p></div>

      <p>The following <code>DOMException</code> types are used in this specification.</p>

      <table class="exceptiontable">
        <tbody><tr>
          <th>Type</th>
          <th>Description</th>
        </tr>
        <tr>
          <td><code><dfn id="dfn-invalidstateerror">InvalidStateError</dfn></code></td>
          <td>Thrown when the <a href="#widl-Event-type"><code>Event.type</code></a> was not specified by initializing the event before <code>dispatchEvent</code> was
            called. Also thrown when the <a href="#interface-Event"><code>Event</code></a> object provided to <code>dispatchEvent</code> is already being dispatched.</td>
        </tr>
        <tr>
          <td><code><dfn id="dfn-notsupportederror">NotSupportedError</dfn></code></td>
          <td>Thrown when <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent()</code></a> is passed an <a href="#interface-Event"><code>Event</code></a>
            interface that the implementation does not support.</td>
        </tr>
      </tbody></table>
    </section>  <!-- event-exceptions -->

    <section property="bibo:hasPart" resource="#event-constructors" typeof="bibo:Chapter" id="event-constructors">
      <h3 resource="#h-event-constructors" id="h-event-constructors"><span property="xhv:role" resource="xhv:heading"><span class="secno">3.7 </span>Constructing Mouse and Keyboard Events</span></h3>

      <p>Generally, when a constructor of an <a href="#interface-Event"><code>Event</code></a> interface,
        or of an interface inherited from the <a href="#interface-Event"><code>Event</code></a> interface,
        is invoked, the steps described in DOM4 [<a href="#references-DOM4">DOM4</a>] should be followed.
        However the <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> and
        <a href="#interface-MouseEvent"><code>MouseEvent</code></a> interfaces provide additional
        dictionary members for initializing the internal state of the
        <a href="#interface-Event"><code>Event</code></a> object's key modifiers: specifically, the
        internal state queried for using the
        <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
        and <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a>
        methods. This section supplements the DOM4 steps for intializing a new
        <a href="#interface-Event"><code>Event</code></a> object with these optional modifier states.
        </p>

      <p>For the purposes of constructing a <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>,
        <a href="#interface-MouseEvent"><code>MouseEvent</code></a>, or object derived from these objects
        using the algorithm below, all
        <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>,
        <a href="#interface-MouseEvent"><code>MouseEvent</code></a>, and derived ojects have
        <dfn id="internal-key-modifier-state">internal key modifier state</dfn> which can be set and
        retreived using the <a href="#keys-modifiers">key modifier names</a>:
          <code title="Key Value" class="key">'AltGraph'</code>
          <code title="Key Value" class="key">'CapsLock'</code>
          <code title="Key Value" class="key">'Fn'</code>
          <code title="Key Value" class="key">'FnLock'</code>
          <code title="Key Value" class="key">'Hyper'</code>
          <code title="Key Value" class="key">'NumLock'</code>
          <code title="Key Value" class="key">'OS'</code>
          <code title="Key Value" class="key">'ScrollLock'</code>
          <code title="Key Value" class="key">'Super'</code>
          <code title="Key Value" class="key">'Symbol'</code> and
          <code title="Key Value" class="key">'SymbolLock'</code>.

      </p><p>The following steps supplement the algorithm defined for constructing events in DOM4:</p>

      <ol>
        <li>If the <a href="#interface-Event"><code>Event</code></a> being constructed is a
          <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> or
          <a href="#interface-MouseEvent"><code>MouseEvent</code></a> object or an object that
          derives from either of these, and a
          <a href="#event-modifier-initializers">EventModifierInit</a>
          argument was provided to the constructor, then run the following sub-steps:
        <ol>
          <li>For each <a href="#event-modifier-initializers">EventModifierInit</a>
            argument, if the dictionary member begins with the string <code>"keyModifierState"</code>, then
            let the <dfn id="modifier-key-name">key modifier name</dfn> be the dictionary member's name
            excluding the prefix <code>"keyModifierState"</code>, and set the
            <a href="#interface-Event"><code>Event</code></a> object's
            <a href="#internal-key-modifier-state">internal key modifier state</a> that
            matches the <a href="#modifier-key-name">key modifier name</a> to the corresponding value.
        </li></ol>
      </li></ol>
    </section>
  </section>  <!-- dom-event-architecture -->

  <!-- Section 4: Basic Event Interfaces ========================================================-->
  <section property="bibo:hasPart" resource="#event-interfaces" typeof="bibo:Chapter" id="event-interfaces">
    <!--OddPage--><h2 resource="#h-event-interfaces" id="h-event-interfaces"><span property="xhv:role" resource="xhv:heading"><span class="secno">4. </span>Basic Event Interfaces</span></h2>

    <p>The basic event interfaces defined in DOM4
      [<a href="#references-DOM4">DOM4</a>] are fundamental to UI Events.
      These basic event interfaces <em title="MUST" class="rfc2119">MUST</em> always be supported by the implementation:
      </p>

    <ul>
      <li>The <dfn id="interface-Event"><code>Event</code></dfn> interface and its following constants, methods and attributes:
        <ul>
          <li><dfn id="widl-Event-NONE"><code>NONE</code></dfn> constant</li>
          <li><dfn id="widl-Event-CAPTURING_PHASE"><code>CAPTURING_PHASE</code></dfn> constant</li>
          <li><dfn id="widl-Event-AT_TARGET"><code>AT_TARGET</code></dfn> constant</li>
          <li><dfn id="widl-Event-BUBBLING_PHASE"><code>BUBBLING_PHASE</code></dfn> constant</li>
          <li><dfn id="widl-Event-type"><code>type</code></dfn> attribute</li>
          <li><dfn id="widl-Event-target"><code>target</code></dfn> attribute</li>
          <li><dfn id="widl-Event-currentTarget"><code>currentTarget</code></dfn> attribute</li>
          <li><dfn id="widl-Event-eventPhase"><code>eventPhase</code></dfn> attribute</li>
          <li><dfn id="widl-Event-bubbles"><code>bubbles</code></dfn> attribute</li>
          <li><dfn id="widl-Event-cancelable"><code>cancelable</code></dfn> attribute</li>
          <li><dfn id="widl-Event-timeStamp"><code>timeStamp</code></dfn> attribute</li>
          <li><dfn id="widl-Event-defaultPrevented"><code>defaultPrevented</code></dfn> attribute</li>
          <li><dfn id="widl-Event-isTrusted"><code>isTrusted</code></dfn> attribute</li>
          <li><dfn id="widl-Event-stopPropagation"><code>stopPropagation()</code></dfn> method</li>
          <li><dfn id="widl-Event-stopImmediatePropagation"><code>stopImmediatePropagation()</code></dfn> method</li>
          <li><dfn id="widl-Event-preventDefault"><code>preventDefault()</code></dfn> method</li>
          <li><dfn id="widl-Event-initEvent"><code>initEvent()</code></dfn> method</li>
        </ul>
      </li>
      <li>The <dfn id="interface-CustomEvent"><code>CustomEvent</code></dfn> interface and its following method and attribute:
        <ul>
          <li><dfn id="widl-CustomEvent-initCustomEvent"><code>initCustomEvent()</code></dfn> method</li>
          <li><dfn id="widl-CustomEvent-detail"><code>detail</code></dfn> attribute</li>
        </ul>
      </li>
      <li>The <dfn id="interface-EventTarget"><code>EventTarget</code></dfn> interface and its following methods:
        <ul>
          <li><dfn id="widl-EventTarget-addEventListener"><code>addEventListener()</code></dfn> method</li>
          <li><dfn id="widl-EventTarget-removeEventListener"><code>removeEventListener()</code></dfn> method</li>
          <li><dfn id="widl-EventTarget-dispatchEvent"><code>dispatchEvent()</code></dfn> method</li>
        </ul>
      </li>
      <li>The <dfn id="interface-EventListener"><code>EventListener</code></dfn> interface and its <dfn id="widl-EventListener-handleEvent"><code>handleEvent</code></dfn> method</li>
      <li>The <code>Document</code> interface's <dfn id="widl-DocumentEvent-createEvent"><code>createEvent</code></dfn> method</li>
    </ul>

    <p>The event types defined in this specification derive from these basic interfaces, and <em title="MUST" class="rfc2119">MUST</em>
      inherit all of the attributes, methods, and constants of the interfaces they derive from.
      </p>
    <p>The following chart describes the inheritance structure of interfaces defined in this specification.
      </p>

    <figure id="figure-event-inheritance">
      <img src="event-inheritance.svg" alt="Graphical representation of inheritance of interfaces defined by this specification" height="230">
      <figcaption>Fig. <span class="figno">2</span> <span class="fig-title">Graphical representation of inheritance of interfaces defined by this specification</span></figcaption>
    </figure>

    <section property="bibo:hasPart" resource="#event-types-list" typeof="bibo:Chapter" id="event-types-list">
      <h3 resource="#h-event-types-list" id="h-event-types-list"><span property="xhv:role" resource="xhv:heading"><span class="secno">4.1 </span>List of Event Types</span></h3>

      <p>Each event <em title="MUST" class="rfc2119">MUST</em> be associated with a type, called <em>event type</em> and available as the <a href="#widl-Event-type"><code class="interface-attribute">type</code></a>
        attribute on the event object. The event type <em title="MUST" class="rfc2119">MUST</em> be of type <code>DOMString</code>.</p>

      <p>Depending on the level of DOM support, or the devices used for display (e.g., screen) or interaction (e.g., mouse, keyboard, touch screen, or voice), these event
        types can be generated by the implementation. When used with an [<cite><a class="informative" href="#references-XML">XML 1.0</a></cite>] or
        [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>] application, the specifications of those languages <em title="MAY" class="rfc2119">MAY</em> restrict the
        semantics and scope (in particular the possible <a class="def" href="#glossary-event-target">event targets</a>) associated
        with an event type. Refer to the specification defining the language used in order to find those restrictions or to find event types that are
        not defined in this document.</p>

      <p>The following table provides an informative summary of the event types defined in this specification.</p>

      <table class="data-table">
        <tbody><tr>
          <th>Event Type</th>
          <th>Sync / Async</th>
          <th>Bubbling phase</th>
          <th>Trusted event target types</th>
          <th>DOM interface</th>
          <th>Cancelable</th>
          <th>Default Action</th>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-abort"><code>abort</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-Event"><code>Event</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="http://w3c.github.io/editing-explainer/input-events.html#idl-def-InputEvent"><code>InputEvent</code></a></td>
          <td>Yes</td>
          <td>Update the DOM element</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-blur"><code>blur</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td>Yes</td>
          <td>Varies:
            for <a class="def" href="#glossary-event-target">targets</a> with an associated activation
            behavior, executes the <a class="def" href="#glossary-activation-behavior">activation behavior</a>;
            for focusable <a class="def" href="#glossary-event-target">targets</a>, gives the element focus.
          </td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
          <td>Yes</td>
          <td>Show a <a class="def" href="#glossary-text-composition-system">text composition system</a> candidate window</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>Varies:
            for <a class="def" href="#glossary-event-target">targets</a> with an associated activation
            behavior, executes the <a class="def" href="#glossary-activation-behavior">activation behavior</a>;
            for focusable <a class="def" href="#glossary-event-target">targets</a>, gives the element focus;
            for selectable <a class="def" href="#glossary-event-target">targets</a>, selects part or all of the
            element's content.
          </td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-error"><code>error</code></a></td>
          <td>Async</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-Event"><code>Event</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-focus"><code>focus</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-focusout"><code>focusout</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="http://w3c.github.io/editing-explainer/input-events.html#idl-def-InputEvent"><code>InputEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
          <td>Yes</td>
          <td>Varies:
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a> and <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a> events;
            launch <a class="def" href="#glossary-text-composition-system">text composition system</a>;
            <a class="eventtype" href="#event-type-blur"><code>blur</code></a> and <a class="eventtype" href="#event-type-focus"><code>focus</code></a> events;
            <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event;
            <a class="def" href="#glossary-activation-behavior">activation behavior</a>;
            other event</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
          <td>Yes</td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-load"><code>load</code></a></td>
          <td>Async</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>Element</code></td>
          <td><a href="#interface-Event"><code>Event</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td>Yes</td>
          <td>Varies: start a drag/drop operation; start a text selection; start a scroll/pan interaction (in combination with the middle mouse button, if supported)</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td><a href="#mousemove-now-cancelable">Yes</a></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td>Yes</td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td>Yes</td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
          <td>Yes</td>
          <td>Invoke a context menu (in combination with the right mouse button, if supported)</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-resize"><code>resize</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
          <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-scroll"><code>scroll</code></a></td>
          <td>Async</td>
          <td><abbr title="Number, Other">No</abbr> / <a href="#scroll-document">Yes</a></td>
          <td><code>Document</code>, <code>Element</code></td>
          <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-select"><code>select</code></a></td>
          <td>Sync</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-Event"><code>Event</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-unload"><code>unload</code></a></td>
          <td>Sync</td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>Element</code></td>
          <td><a href="#interface-Event"><code>Event</code></a></td>
          <td><abbr title="Number, Other">No</abbr></td>
          <td>None</td>
        </tr>
        <tr>
          <td><a class="eventtype" href="#event-type-wheel"><code>wheel</code></a></td>
          <td>Async</td>
          <td>Yes</td>
          <td><code>Element</code></td>
          <td><a href="#interface-WheelEvent"><code>WheelEvent</code></a></td>
          <td>Yes</td>
          <td>Scroll (or zoom) the document</td>
        </tr>
      </tbody></table>

      <p>For a list of events which are deprecated in this specification, see the <a href="#legacy-event-types">Legacy Event Types</a> appendix
        at the end of this document.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>The following is one way to interpret the above tables: the <a class="eventtype" href="#event-type-load"><code>load</code></a> event will
        trigger event listeners attached on <code>Element</code> nodes for that event and on the capture and target phases. This event is not cancelable. If an event listener for the
        <a class="eventtype" href="#event-type-load"><code>load</code></a> event is attached to a node other than <a class="def" href="#glossary-window"><code>Window</code></a>,
        <code>Document</code>, or <code>Element</code> nodes, or if it is attached to the bubbling phase only, this event listener would not be triggered.</p>
      </div>

      <div class="note"><div id="h-note7" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>Don't interpret the above tables as definitive for the listed event types. For example, the <a href="#dfn-load" class="eventtype internalDFN"><code>load</code></a> event is used in other
        specifications, for example, in XMLHttpRequest. Similarly, <a href="#widl-EventTarget-dispatchEvent"><code>dispatchEvent</code></a> can be used to dispatch untrusted events to
        listeners on <strong>any</strong> object that also implements <a href="#interface-EventTarget"><code>EventTarget</code></a>.</p></div>

      <div class="note"><div id="h-note8" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>The event objects associated with the event types described above contain additional context information--refer to the description of the DOM
        interfaces for further information.</p></div>
    </section>  <!-- event-types-list -->

  </section>  <!-- event-interfaces  -->

  <!-- Section 5: The Events ========================================================-->
  <section property="bibo:hasPart" resource="#event-types" typeof="bibo:Chapter" id="event-types">
    <!--OddPage--><h2 resource="#h-event-types" id="h-event-types"><span property="xhv:role" resource="xhv:heading"><span class="secno">5. </span>Event Types</span></h2>
    <p>The DOM Event Model allows a DOM implementation to support multiple modules of events.
      The model has been designed to allow addition of new event modules in the future.
      This document does not attempt to define all possible events.
      For purposes of interoperability, the DOM defines a module of user interface events
      including lower level device dependent events and a module of document mutation events.
      </p>

    <section property="bibo:hasPart" resource="#events-uievents" typeof="bibo:Chapter" id="events-uievents">
      <h3 resource="#h-events-uievents" id="h-events-uievents"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.1 </span>User Interface Event Types</span></h3>
      <p>The User Interface event module contains basic event types associated with user
        interfaces and document manipulation.
        </p>

      <section property="bibo:hasPart" resource="#interface-UIEvent" typeof="bibo:Chapter" id="interface-UIEvent">
        <h4 resource="#h-interface-uievent" id="h-interface-uievent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.1.1 </span>Interface UIEvent</span></h4>

        <p class="intro-dom">Introduced in DOM Level 2</p>

        <p>The <code>UIEvent</code> interface provides specific contextual information associated
          with User Interface events.
          </p>

        <p>To create an instance of the <code>UIEvent</code> interface, use the
          <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("UIEvent")</code></a>
          method call.
          </p>

        <pre class="idl"><span class="idlInterface" id="idl-def-UIEvent">[<span class="extAttr">Constructor(DOMString type, optional UIEventInit eventInitDict)</span>]
interface <span class="idlInterfaceID">UIEvent</span> : <span class="idlSuperclass"><a class="internalDFN" href="#dfn-event">Event</a></span> {
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlAttrName"><a href="#widl-UIEvent-view">view</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">long</span>    <span class="idlAttrName"><a href="#widl-UIEvent-detail">detail</a></span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes" typeof="bibo:Chapter" id="attributes"><h5 resource="#h-attributes" id="h-attributes"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.1.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-UIEvent-detail"><code>detail</code> of type <span class="idlAttrType">long</span>, readonly   </dt><dd>
            <p>Specifies some detail information about the <a href="#interface-Event"><code>Event</code></a>, depending on the type of event.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.</p>
          </dd><dt id="widl-UIEvent-view"><code>view</code> of type <span class="idlAttrType"><a class="internalDFN" href="#dfn-window">Window</a></span>, readonly   , nullable</dt><dd>
            <p>The <code>view</code> attribute identifies the <code>Window</code> from which the event was generated.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>null</code>.</p>
          </dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-UIEventInit">dictionary <span class="idlDictionaryID">UIEventInit</span> : <span class="idlSuperclass">EventInit</span> {
<span class="idlMember">    <span class="idlMemberType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlMemberName"><a href="#widl-UIEventInit-view">view</a></span> = <span class="idlMemberValue">null</span>;</span>
<span class="idlMember">    <span class="idlMemberType">long</span>    <span class="idlMemberName"><a href="#widl-UIEventInit-detail">detail</a></span> = <span class="idlMemberValue">0</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-uieventinit-members" typeof="bibo:Chapter" id="dictionary-uieventinit-members"><h5 resource="#h-dictionary-uieventinit-members" id="h-dictionary-uieventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.1.1.2 </span>Dictionary <a href="#idl-def-UIEventInit" class="idlType"><code>UIEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-UIEventInit-detail"><code>detail</code> of type <span class="idlMemberType">long</span>, defaulting to <code>0</code></dt><dd>
            <p>This value is initialized to a number that is application-specific.
              </p>
          </dd><dt id="widl-UIEventInit-view"><code>view</code> of type <span class="idlMemberType"><a class="internalDFN" href="#dfn-window">Window</a></span>, nullable, defaulting to <code>null</code></dt><dd>
            <p>Should be initialized to the Window object of the global environment
              in which this event will be dispatched. If this event will be dispatched
              to an element, the view property should be set to the Window object
              containing the element's <code>ownerDocument</code>.
              </p>
          </dd></dl></section>

      </section>  <!-- interface-UIEvent -->

      <p>The User Interface event types are listed below.  Some of these events use the
        <a href="#interface-UIEvent"><code>UIEvent</code></a> interface if generated from a
        user interface, but the <a href="#interface-Event"><code>Event</code></a> interface
        otherwise, as detailed in each event.
        </p>

      <!-- load -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-load"><dfn id="dfn-load"><a class="eventtype" href="#event-type-load"><code>load</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>load</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a> if generated from a user interface, <a href="#interface-Event"><code>Event</code></a> otherwise.</td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Async</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      common object whose contained resources have loaded</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when the DOM implementation finishes loading the resource (such as the document)
              and any dependent resources (such as images, style sheets, or scripts). Dependent resources that fail to load <em title="MUST NOT" class="rfc2119">MUST NOT</em> prevent this event from firing if the resource
              that loaded them is still accessible via the DOM. If this event type is dispatched, implementations are <em title="REQUIRED" class="rfc2119">REQUIRED</em> to dispatch this event at least on the <code>Document</code>
              node.</p>

            <div class="note"><div id="h-note9" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> For legacy reasons, <a class="eventtype" href="#event-type-load"><code>load</code></a> events for resources inside
              the document (e.g., images) do not include the <a class="def" href="#glossary-window">Window</a> in the propagation path in HTML implementations. See
              [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>] for more information.</p></div>
          </dd>
        </dl>
      </div>

      <!-- unload -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-unload"><dfn id="dfn-unload"><a class="eventtype" href="#event-type-unload"><code>unload</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>unload</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a> if generated from a user interface, <a href="#interface-Event"><code>Event</code></a> otherwise.</td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      common object whose contained resources have been removed</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when the DOM Implementation removes from the environment the resource (such
              as the document) or any dependent resources (such as images, style sheets, scripts). The document <em title="MUST" class="rfc2119">MUST</em> be unloaded after the dispatch of this event type. If this
              event type is dispatched, implementations are <em title="REQUIRED" class="rfc2119">REQUIRED</em> to dispatch this event at least on the <code>Document</code> node.</p>
          </dd>
        </dl>
      </div>

      <!-- abort -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-abort"><dfn id="dfn-abort"><a class="eventtype" href="#event-type-abort"><code>abort</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>abort</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a> if generated from a user interface, <a href="#interface-Event"><code>Event</code></a> otherwise.</td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element whose resources have been stopped from loading without error</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when the loading of a resource has been aborted, such as by a user canceling
              the load while it is still in progress.</p>
          </dd>
        </dl>
      </div>

      <!-- error -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-error"><dfn id="dfn-error"><a class="eventtype" href="#event-type-error"><code>error</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>error</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a> if generated from a user interface, <a href="#interface-Event"><code>Event</code></a> otherwise.</td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Async</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element whose resources have been stopped from loading due to an error</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a resource failed to load, or has been loaded but cannot be interpreted
              according to its semantics, such as an invalid image, a script execution error, or non-well-formed XML.</p>
          </dd>
        </dl>
      </div>

      <!-- select -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-select"><dfn id="dfn-select"><a class="eventtype" href="#event-type-select"><code>select</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>select</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a> if generated from a user interface, <a href="#interface-Event"><code>Event</code></a> otherwise.</td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element whose text content has been selected</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a user selects some text.  This event is dispatched after the selection
              has occurred.</p>

            <p>This specification does not provide contextual information to access the selected text.  Where applicable, a <a class="def" href="#glossary-host-language">host
              language</a> <em title="SHOULD" class="rfc2119">SHOULD</em> define rules for how a user <em title="MAY" class="rfc2119">MAY</em> select content (with consideration for international language conventions), at what point the <a class="eventtype" href="#event-type-select"><code>select</code></a> event is dispatched, and how a content author <em title="MAY" class="rfc2119">MAY</em> access the user-selected content.</p>

            <div class="note"><div id="h-note10" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>  In order to access to user-selected content, content authors will use native capabilities of the <a class="def" href="#glossary-host-language">host languages</a>, such as the <code>Document.getSelection()</code> method of the <a href="https://dvcs.w3.org/hg/editing/raw-file/tip/editing.html#selections">
              HTML Editing APIs</a> [<cite><a class="informative" href="#references-HTMLEd">HTML Editing</a></cite>].</p></div>

            <div class="note"><div id="h-note11" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <a class="eventtype" href="#event-type-select"><code>select</code></a> event might not be available
              for all elements in all languages.  For example, in [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>], <a class="eventtype" href="#event-type-select">
              <code>select</code></a> events can be dispatched only on form <code>input</code> and <code>textarea</code> elements.  Implementations can dispatch <a class="eventtype" href="#event-type-select"><code>select</code></a> events in any context deemed appropriate, including text selections outside of form controls, or image or
              markup selections such as in SVG.</p></div>
          </dd>
        </dl>
      </div>

      <!-- resize -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-resize"><dfn id="dfn-resize"><a class="eventtype" href="#event-type-resize"><code>resize</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>resize</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      object which has been resized</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a document view has been resized. This event type is dispatched after
              all effects for that occurrence of resizing of that particular <a class="def" href="#glossary-event-target">event target</a> have been executed by the <a class="def" href="#glossary-user-agent">user agent</a>.</p>

            <p><a class="def" href="#glossary-user-agent">User agents</a> which support continuous reflow of the document's layout during user-initiated resizing <em title="MUST" class="rfc2119">MUST</em> dispatch
              this event synchronously after each reflow of the document.</p>

            <p>The <a class="def" href="#glossary-window"><code>Window</code></a> object <em title="SHOULD" class="rfc2119">SHOULD</em> always be resizable.  A <a class="def" href="#glossary-host-language">
              host language</a> <em title="MAY" class="rfc2119">MAY</em> define certain elements to be resizable, and under what conditions (e.g., specific elements like <code>&lt;iframe&gt;</code>, or elements
              with particular characteristics like width and height). However, this specification does not define the behavior for elements.</p>

            <div class="note"><div id="h-note12" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>  The <a class="eventtype" href="#event-type-resize"><code>resize</code></a> event is distinct from the
              SVG <code class="eventtype">zoom</code> event types, though both can occur at the same time, or as the consequence of the same user action.  In particular, browser
              <q>font zooming</q> or <q>page zooming</q> will not necessarily trigger a <a class="eventtype" href="#event-type-resize"><code>resize</code></a> event.</p></div>

            <div class="note"><div id="h-note13" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> In previous DOM Events specifications, the <a class="eventtype" href="#event-type-resize"><code>resize</code></a>
              event type was defined to have a <a class="def" href="#glossary-bubbling-phase">bubbling phase</a>, but for performance reasons, this was not implemented in most
              user agents, and this specification removes the <a class="def" href="#glossary-bubbling-phase">bubbling phase</a> for this event.</p></div>
          </dd>
        </dl>
      </div>

      <!-- scroll -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-scroll"><dfn id="dfn-scroll"><a class="eventtype" href="#event-type-scroll"><code>scroll</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>scroll</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Async</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr> / <a href="#scroll-document">Yes</a></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Document</code>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      object which has been scrolled</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a document view or an element has been scrolled.  This event type is dispatched
              after the scroll has occurred.</p>

            <p id="scroll-document">When dispatched on the <code>Document</code> element, this event type <em title="MUST" class="rfc2119">MUST</em>
              bubble to the <a class="def" href="#glossary-window"><code>Window</code></a> object.</p>
          </dd>
        </dl>
      </div>
    </section>

    <section property="bibo:hasPart" resource="#events-focusevent" typeof="bibo:Chapter" id="events-focusevent">
      <h3 resource="#h-events-focusevent" id="h-events-focusevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2 </span>Focus Event Types</span></h3>

      <div class="note"><div id="h-note14" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        This interface and its associated event types and
          <a href="#events-focusevent-event-order">focus event order</a>
        were designed in accordance to the concepts and guidelines defined in
          <a href="http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100308/">User Agent Accessibility Guidelines 2.0</a>
          [<a href="#references-UAAG2">UAAG 2.0</a>],
        with particular attention on the
          <a href="http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100308/#gl-focus-mechanism">focus mechanism</a>
        and the terms defined in the
          <a href="http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100308/#def-focus">glossary entry for focus</a>.
        </p></div>

      <section property="bibo:hasPart" resource="#interface-FocusEvent" typeof="bibo:Chapter" id="interface-FocusEvent">
        <h4 resource="#h-interface-focusevent" id="h-interface-focusevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2.1 </span>Interface FocusEvent</span></h4>

        <p class="intro-dom">Introduced in this specification</p>

        <p>The <code>FocusEvent</code> interface provides specific contextual information associated
          with Focus events.
          </p>

        <p>To create an instance of the <code>FocusEvent</code> interface, use the
          <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("FocusEvent")</code></a>
          method call.
          </p>

        <pre class="idl"><span class="idlInterface" id="idl-def-FocusEvent">[<span class="extAttr">Constructor(DOMString typeArg, optional FocusEventInit focusEventInitDict)</span>]
interface <span class="idlInterfaceID">FocusEvent</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEvent"><code>UIEvent</code></a></span> {
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span> <span class="idlAttrName"><a href="#widl-FocusEvent-relatedTarget">relatedTarget</a></span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-1" typeof="bibo:Chapter" id="attributes-1"><h5 resource="#h-attributes-1" id="h-attributes-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-FocusEvent-relatedTarget"><code>relatedTarget</code> of type <span class="idlAttrType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></span>, readonly   , nullable</dt><dd>
            <p>Used to identify a secondary <a href="#interface-EventTarget"><code>EventTarget</code></a>
              related to a Focus event, depending on the type of event.
              </p>

            <p>For security reasons with nested browsing contexts, when tabbing into or out of a nested
              context, the relevant EventTarget <em title="SHOULD" class="rfc2119">SHOULD</em> be <code>null</code>.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>null</code>.
              </p>
          </dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-FocusEventInit">dictionary <span class="idlDictionaryID">FocusEventInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEventInit"><code>UIEventInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span> <span class="idlMemberName"><a href="#widl-FocusEventInit-relatedTarget">relatedTarget</a></span> = <span class="idlMemberValue">null</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-focuseventinit-members" typeof="bibo:Chapter" id="dictionary-focuseventinit-members"><h5 resource="#h-dictionary-focuseventinit-members" id="h-dictionary-focuseventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2.1.2 </span>Dictionary <a href="#idl-def-FocusEventInit" class="idlType"><code>FocusEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-FocusEventInit-relatedTarget"><code>relatedTarget</code> of type <span class="idlMemberType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></span>, nullable, defaulting to <code>null</code></dt><dd>
            <p>The <code>relatedTarget</code> should be initialized to the element
              whose bounds the mouse pointer just left (in the case of a
              <em>mouseover</em> or <em>mouseenter</em> event) or the element
              whose bounds the mouse pointer is entering (in the case of a
              <em>mouseout</em> or <em>mouseleave</em>
              or <em>focusout</em> event). For other events, this value need not
              be assigned (and will default to null).
              </p>
          </dd></dl></section>

      </section>  <!-- interface-FocusEvent -->

      <section property="bibo:hasPart" resource="#events-focusevent-event-order" typeof="bibo:Chapter" id="events-focusevent-event-order">
        <h4 resource="#h-events-focusevent-event-order" id="h-events-focusevent-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2.2 </span>Focus Event Order</span></h4>
        <p>
          The focus events defined in this specification occur in a set order relative to one another.  The following is the typical sequence of events when a focus is shifted
          between elements (this order assumes that no element is initially focused):</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em>User shifts focus</em></td>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></td>
            <td>Sent before first target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-focus"><code>focus</code></a></td>
            <td>Sent after first target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em>User shifts focus</em></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-focusout"><code>focusout</code></a></td>
            <td>Sent before first target element loses focus</td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></td>
            <td>Sent before second target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-blur"><code>blur</code></a></td>
            <td>Sent after first target element loses focus</td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-focus"><code>focus</code></a></td>
            <td>Sent after second target element receives focus</td>
          </tr>
        </tbody></table>

        <div class="note"><div id="h-note15" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>  This specification does not define the behavior of focus events when interacting with methods such as <code>focus()</code> or
          <code>blur()</code>. See the relevant specifications where those methods are defined for such behavior.</p></div>
      </section>  <!-- events-focusevent-event-order -->

      <section property="bibo:hasPart" resource="#events-focusevent-doc-focus" typeof="bibo:Chapter" id="events-focusevent-doc-focus">
        <h4 resource="#h-events-focusevent-doc-focus" id="h-events-focusevent-doc-focus"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.2.3 </span>Document Focus and Focus Context</span></h4>

        <p>This event module includes event types for notification of changes in document
          <a class="def" href="#glossary-event-focus">focus</a>.
          There are three distinct focus contexts that are relevant to this discussion:
          </p>

        <ul>
          <li>The <em>operating system focus context</em> which <em title="MAY" class="rfc2119">MAY</em> be on one of many different applications currently
            running on the computer. One of these applications with focus can be a browser.
            </li>
          <li>When the browser has focus, the user can switch (such as with the tab key) the
            <em>application focus context</em> among the different browser user interface fields (e.g., the
            Web site location bar, a search field, etc.). One of these user interface fields can be the
            document being shown in a tab.
            </li>
          <li>When the document itself has focus, the <em>document focus context</em> can be set to any of the
            focusable elements in the document.
            </li>
        </ul>

        <p>The event types defined in this specification deal exclusively with document focus, and the
          <a class="def" href="#glossary-event-target">event target</a> identified in the event details
          <em title="MUST" class="rfc2119">MUST</em> only be part of the document or documents in the window, never a part of the browser or
          operating system, even when switching from one focus context to another.
          </p>

        <p>Normally, a document always has a focused element (even if it is the document element itself) and a persistent <a class="def" href="#glossary-event-focus-ring">focus
          ring</a>. When switching between focus contexts, the document's currently focused element and focus ring normally remain in their current state. For example,
          if a document has three focusable elements, with the second element focused, when a user changes operating system focus to another application and then back to
          the browser, the second element will still be focused within the document, and tabbing will change the focus to the third element.  A <a class="def" href="#glossary-host-language">
          host language</a> <em title="MAY" class="rfc2119">MAY</em> define specific elements which might receive focus, the conditions under which an element <em title="MAY" class="rfc2119">MAY</em> receive focus, the means by which
          focus <em title="MAY" class="rfc2119">MAY</em> be changed, and the order in which the focus changes.  For example, in some cases an element might be given focus by moving a pointer over it, while other
          circumstances might require a mouse click. Some elements might not be focusable at all, and some might be focusable only by special means (clicking on the element),
          but not by tabbing to it.  Documents <em title="MAY" class="rfc2119">MAY</em> contain multiple focus rings.  Other specifications <em title="MAY" class="rfc2119">MAY</em> define a more complex focus model than is described in this specification,
          including allowing multiple elements to have the current focus.
          </p>
      </section>  <!-- events-focusevent-doc-focus -->

      <p>The Focus event types are listed below.</p>

      <!-- blur -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-blur"><dfn id="dfn-blur"><a class="eventtype" href="#event-type-blur"><code>blur</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>blur</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> losing focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> receiving focus.</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when an <a class="def" href="#glossary-event-target">event target</a> loses
              focus. The focus <em title="MUST" class="rfc2119">MUST</em> be taken from the element before the dispatch of this event type.  This event type is similar to <a class="eventtype" href="#event-type-focusout">
              <code>focusout</code></a>, but is dispatched after focus is shifted, and does not bubble.</p>
          </dd>
        </dl>
      </div>

      <!-- focus -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-focus"><dfn id="dfn-focus"><a class="eventtype" href="#event-type-focus"><code>focus</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>focus</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> receiving focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> losing focus (if any).</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when an <a class="def" href="#glossary-event-target">event target</a> receives
              focus. The focus <em title="MUST" class="rfc2119">MUST</em> be given to the element before the dispatch of this event type.  This event type is similar to <a class="eventtype" href="#event-type-focusin">
              <code>focusin</code></a>, but is dispatched after focus is shifted, and does not bubble.</p>
          </dd>
        </dl>
      </div>

      <!-- focusin -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-focusin"><dfn id="dfn-focusin"><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>focusin</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> receiving focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> losing focus (if any).</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when an <a class="def" href="#glossary-event-target">event target</a> is about
              to receive focus. This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched before the element is given focus.  The <a class="def" href="#glossary-event-target">event target</a> <em title="MUST" class="rfc2119">MUST</em>
              be the element which is about to receive focus.  This event type is similar to <a class="eventtype" href="#event-type-focus"><code>focus</code></a>, but is dispatched
              before focus is shifted, and does bubble.</p>

            <div class="note"><div id="h-note16" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="_9"><strong>Note:</strong> When using this event type, the content author can use the event's <code class="attribute-name"><a href="#widl-FocusEvent-relatedTarget">
              FocusEvent.relatedTarget</a></code> attribute (or a host-language-specific method or means) to get the currently focused element before the focus shifts to the
              next focus <a class="def" href="#glossary-event-target">event target</a>, thus having access to both the element losing focus and the element gaining focus
              without the use of the <a class="eventtype" href="#event-type-blur"><code>blur</code></a> or <a class="eventtype" href="#event-type-focusout"><code>focusout</code></a> event
              types.</p></div>
          </dd>
        </dl>
      </div>

      <!-- focusout -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-focusout"><dfn id="dfn-focusout"><a class="eventtype" href="#event-type-focusout"><code>focusout</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>focusout</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> losing focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> receiving focus.</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>
            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when an <a class="def" href="#glossary-event-target">event target</a> is about
              to lose focus. This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched before the element loses focus.  The <a class="def" href="#glossary-event-target">event target</a> <em title="MUST" class="rfc2119">MUST</em> be the
              element which is about to lose focus.  This event type is similar to <a class="eventtype" href="#event-type-blur"><code>blur</code></a>, but is dispatched before
              focus is shifted, and does bubble.</p>
          </dd>
        </dl>
      </div>
    </section>  <!-- events-focusevent -->

    <section property="bibo:hasPart" resource="#events-mouseevents" typeof="bibo:Chapter" id="events-mouseevents">
      <h3 resource="#h-events-mouseevents" id="h-events-mouseevents"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3 </span>Mouse Event Types</span></h3>

      <p>The mouse event module originates from the [<cite><a class="informative" href="#references-HTML40">HTML 4.01</a></cite>] <code>onclick</code>, <code>ondblclick</code>,
        <code>onmousedown</code>, <code>onmouseup</code>, <code>onmouseover</code>, <code>onmousemove</code>, and <code>onmouseout</code> attributes. This event module
        is specifically designed for use with pointing input devices, such as a mouse or a trackball.</p>

      <section property="bibo:hasPart" resource="#interface-MouseEvent" typeof="bibo:Chapter" id="interface-MouseEvent">
        <h4 resource="#h-interface-mouseevent" id="h-interface-mouseevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.1 </span>Interface MouseEvent</span></h4>

        <p class="intro-dom">Introduced in DOM Level 2, modified in this specification</p>

        <p>The <code>MouseEvent</code> interface provides specific contextual information
          associated with Mouse events.
          </p>

        <p>In the case of nested elements, mouse events are always targeted at the most deeply
          nested element.
          </p>

        <div class="note"><div id="h-note17" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          Ancestors of the targeted element can use event bubbling to obtain notifications
          of mouse events which occur within their descendent elements.
          </p></div>

        <p>To create an instance of the <code>MouseEvent</code> interface, use the
          <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("MouseEvent")</code></a>
          method call.
          </p>

        <div class="note"><div id="h-note18" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          When initializing <code>MouseEvent</code> objects using <code>initMouseEvent</code>,
          implementations can use the client coordinates <code>clientX</code> and <code>clientY</code>
          for calculation of other coordinates (such as target coordinates exposed by
            <a class="def" href="#glossary-DOM-Level-0">DOM Level 0</a>
          implementations or other proprietary attributes, e.g., <code>pageX</code>).
          </p></div>

        <pre class="idl"><span class="idlInterface" id="idl-def-MouseEvent">[<span class="extAttr">Constructor(DOMString typeArg, optional MouseEventInit mouseEventInitDict)</span>]
interface <span class="idlInterfaceID">MouseEvent</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEvent"><code>UIEvent</code></a></span> {
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">long</span>           <span class="idlAttrName"><a href="#widl-MouseEvent-screenX">screenX</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">long</span>           <span class="idlAttrName"><a href="#widl-MouseEvent-screenY">screenY</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">long</span>           <span class="idlAttrName"><a href="#widl-MouseEvent-clientX">clientX</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">long</span>           <span class="idlAttrName"><a href="#widl-MouseEvent-clientY">clientY</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>        <span class="idlAttrName"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>        <span class="idlAttrName"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>        <span class="idlAttrName"><a href="#widl-MouseEvent-altKey">altKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>        <span class="idlAttrName"><a href="#widl-MouseEvent-metaKey">metaKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">short</span>          <span class="idlAttrName"><a href="#widl-MouseEvent-button">button</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span>   <span class="idlAttrName"><a href="#widl-MouseEvent-relatedTarget">relatedTarget</a></span>;</span>
<span class="idlSectionComment">    // Introduced in this specification</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned short</span> <span class="idlAttrName"><a href="#widl-MouseEvent-buttons">buttons</a></span>;</span>
<span class="idlMethod">    <span class="idlMethType">boolean</span> <span class="idlMethName"><a href="#widl-MouseEvent-getModifierState">getModifierState</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">keyArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-2" typeof="bibo:Chapter" id="attributes-2"><h5 resource="#h-attributes-2" id="h-attributes-2"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-MouseEvent-altKey"><code>altKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p>Refer to the <a href="#widl-KeyboardEvent-altKey"><code>KeyboardEvent.altKey</code></a> attribute.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.
              </p>
          </dd><dt id="widl-MouseEvent-button"><code>button</code> of type <span class="idlAttrType">short</span>, readonly   </dt><dd>
            <p>During mouse events caused by the depression or release of a mouse button,
              <code>button</code> <em title="MUST" class="rfc2119">MUST</em> be used to indicate which pointer device button
              changed state.
              </p>

            <p>The value of the <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a>
              attribute <em title="MUST" class="rfc2119">MUST</em> be as follows:
              </p>

            <ul>
              <li><code>0</code> <em title="MUST" class="rfc2119">MUST</em> indicate the primary button of the device
                (in general, the left button  or the only button on single-button devices,
                used to activate a user interface control or select text) or the
                un-initialized value.</li>
              <li><code>1</code> <em title="MUST" class="rfc2119">MUST</em> indicate the auxiliary button
                (in general, the middle button, often combined with a mouse wheel).</li>
              <li><code>2</code> <em title="MUST" class="rfc2119">MUST</em> indicate the secondary button
                (in general, the right button, often used to display a context menu).</li>
            </ul>

            <p>Some pointing devices provide or simulate more button states, and values higher than
              <code>2</code> or lower than <code>0</code> <em title="MAY" class="rfc2119">MAY</em> be used to represent such buttons.
              </p>

            <div class="note"><div id="h-note19" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              The value of <code>button</code> is not updated for events not caused by the
              depression/release of a mouse button.
              In these scenarios, take care not to interpret the value <code>0</code> as the
              left button, but rather as the
                <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>.
              </p></div>

            <div class="note"><div id="h-note20" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
              Some <a class="def" href="#glossary-default-action">default actions</a> related
              to events such as <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a> and
              <a href="#dfn-mouseup" class="eventtype internalDFN"><code>mouseup</code></a> depend on the specific mouse
              button in use.
              </p></div>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-buttons"><code>buttons</code> of type <span class="idlAttrType">unsigned short</span>, readonly   </dt><dd>
            <p>During any mouse events, <code>buttons</code> <em title="MUST" class="rfc2119">MUST</em> be used to indicate
              which combination of mouse buttons are currently being pressed,
              expressed as a bitmask.
              </p>

            <div class="note"><div id="h-note21" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              Though similarly named, the values for the <code>buttons</code> attribute
              and the <a href="#widl-MouseEvent-button"><code>button</code></a>
              attribute are very different.
              The value of <code>button</code> is assumed to be valid during
              <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a> /
              <a href="#dfn-mouseup" class="eventtype internalDFN"><code>mouseup</code></a> event handlers,
              whereas the <code>buttons</code> attribute reflects the state of the
              mouse's buttons for any trusted <code>MouseEvent</code> object
              (while it is being dispatched), because it can represent the
              "no button currently active" state (0).
              </p></div>

            <p>The value of the <a href="#widl-MouseEvent-buttons"><code>MouseEvent.buttons</code></a>
              attribute <em title="MUST" class="rfc2119">MUST</em> be as follows:
              </p>

            <ul>
              <li><code>0</code> <em title="MUST" class="rfc2119">MUST</em> indicate no button is currently active.</li>
              <li><code>1</code> <em title="MUST" class="rfc2119">MUST</em> indicate the primary button of the device
                (in general, the left button or the only button on single-button devices,
                used to activate a user interface control or select text).</li>
              <li><code>2</code> <em title="MUST" class="rfc2119">MUST</em> indicate the secondary button
                (in general, the right button, often used to display a context menu), if present.</li>
              <li><code>4</code> <em title="MUST" class="rfc2119">MUST</em> indicate the auxiliary button
                (in general, the middle button, often combined with a mouse wheel).</li>
            </ul>

            <p>Some pointing devices provide or simulate more buttons.
              To represent such buttons, the value <em title="MUST" class="rfc2119">MUST</em> be doubled for each successive button
              (in the binary series <code>8</code>, <code>16</code>, <code>32</code>, ... ).
              </p>

            <div class="note"><div id="h-note22" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class="" id="buttons-mask"><strong>Note:</strong>
              Because the sum of any set of button values is a unique number, a content
              author can use a bitwise operation to determine how many buttons are currently
              being pressed and which buttons they are, for an arbitrary number of mouse buttons
              on a device.
              For example, the value <code>3</code> indicates that the left and right button are
              currently both pressed, while the value <code>5</code> indicates that the left and
              middle button are currently both pressed.
              </p></div>

            <div class="note"><div id="h-note23" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
              Some <a class="def" href="#glossary-default-action">default actions</a> related
              to events such as <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a> and
              <a href="#dfn-mouseup" class="eventtype internalDFN"><code>mouseup</code></a> depend on the specific mouse button
              in use.
              </p></div>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-clientX"><code>clientX</code> of type <span class="idlAttrType">long</span>, readonly   </dt><dd>
            <p>The horizontal coordinate at which the event occurred relative to the viewport
              associated with the event.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-clientY"><code>clientY</code> of type <span class="idlAttrType">long</span>, readonly   </dt><dd>
            <p>The vertical coordinate at which the event occurred relative to the viewport
              associated with the event.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-ctrlKey"><code>ctrlKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p>Refer to the <a href="#widl-KeyboardEvent-ctrlKey"><code>KeyboardEvent.ctrlKey</code></a> attribute.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.
              </p>
          </dd><dt id="widl-MouseEvent-metaKey"><code>metaKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p>Refer to the <a href="#widl-KeyboardEvent-metaKey"><code>KeyboardEvent.metaKey</code></a> attribute.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.
              </p>
          </dd><dt id="widl-MouseEvent-relatedTarget"><code>relatedTarget</code> of type <span class="idlAttrType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></span>, readonly   , nullable</dt><dd>
            <p>Used to identify a secondary <a href="#interface-EventTarget"><code>EventTarget</code></a> related to a UI event, depending on the type of event.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>null</code>.</p>
          </dd><dt id="widl-MouseEvent-screenX"><code>screenX</code> of type <span class="idlAttrType">long</span>, readonly   </dt><dd>
            <p>The horizontal coordinate at which the event occurred relative to the origin
              of the screen coordinate system.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-screenY"><code>screenY</code> of type <span class="idlAttrType">long</span>, readonly   </dt><dd>
            <p>The vertical coordinate at which the event occurred relative to the origin
              of the screen coordinate system.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-MouseEvent-shiftKey"><code>shiftKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p>Refer to the <a href="#widl-KeyboardEvent-shiftKey"><code>KeyboardEvent.shiftKey</code></a> attribute.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a>
              of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.
              </p>
          </dd></dl></section><section property="bibo:hasPart" resource="#methods" typeof="bibo:Chapter" id="methods"><h5 resource="#h-methods" id="h-methods"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.1.2 </span>Methods</span></h5><dl class="methods"><dt id="widl-MouseEvent-getModifierState"><code>getModifierState</code></dt><dd>
            <p class="intro-dom">Introduced in this specification</p>

            <p>Queries the state of a modifier using a key value.
              See <a href="#keys-modifiers">Modifier keys</a> for a list of valid (case-sensitive) arguments to this method.
              </p>

            <p>Returns <code>true</code> if it is a modifier key and the modifier is activated,
              <code>false</code> otherwise.
              </p>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">keyArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a> method for a description of this parameter.</p>
              </td></tr></tbody></table><div><em>Return type: </em><code>boolean</code></div></dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-MouseEventInit">dictionary <span class="idlDictionaryID">MouseEventInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-EventModifierInit"><code>EventModifierInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType">long</span>           <span class="idlMemberName"><a href="#widl-MouseEventInit-screenX">screenX</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">long</span>           <span class="idlMemberName"><a href="#widl-MouseEventInit-screenY">screenY</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">long</span>           <span class="idlMemberName"><a href="#widl-MouseEventInit-clientX">clientX</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">long</span>           <span class="idlMemberName"><a href="#widl-MouseEventInit-clientY">clientY</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">short</span>          <span class="idlMemberName"><a href="#widl-MouseEventInit-button">button</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">unsigned short</span> <span class="idlMemberName"><a href="#widl-MouseEventInit-buttons">buttons</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span>   <span class="idlMemberName"><a href="#widl-MouseEventInit-relatedTarget">relatedTarget</a></span> = <span class="idlMemberValue">null</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-mouseeventinit-members" typeof="bibo:Chapter" id="dictionary-mouseeventinit-members"><h5 resource="#h-dictionary-mouseeventinit-members" id="h-dictionary-mouseeventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.1.3 </span>Dictionary <a href="#idl-def-MouseEventInit" class="idlType"><code>MouseEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-MouseEventInit-button"><code>button</code> of type <span class="idlMemberType">short</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>button</code> attribute of the MouseEvent
              object to a number representing the desired state of the button(s)
              of the mouse.
              </p>

            <div class="note"><div id="h-note24" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              The value 0 is used to represent
              the primary mouse button, 1 is used to represent the auxiliary/middle
              mouse button, and 2 to represent the right mouse button.
              Numbers greater than 2 are also possible, but are not specified
              in this document.
              </p></div>
          </dd><dt id="widl-MouseEventInit-buttons"><code>buttons</code> of type <span class="idlMemberType">unsigned short</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>buttons</code> attribute of the MouseEvent
              object to a number representing one <em>or more</em> of the button(s) of the mouse
              that are to be considered active.
              </p>

            <div class="note"><div id="h-note25" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              The <code>buttons</code>
              attribute is a bit-field. If a mask value of 1 is true when applied to
              the value of the bit field, then the primary mouse button is down. If a
              mask value of 2 is true when applied to the value of the bit field, then
              the right mouse button is down. If a mask value of 4 is true when applied
              to the value of the bit field, then the auxiliary/middle button is down.</p></div>

            <div class="example">
              <p>In JavaScript, to initialize the
                <code>buttons</code> attribute as if the right (2) and middle
                button (4) were being pressed simultaneously, the buttons value
                can be assigned as either:<br>
                <code>{ buttons: 2 | 4 }</code><br>
                or:<br>
                <code>{ buttons: 6 }</code>
                </p>
            </div><!-- Initializing buttons -->
          </dd><dt id="widl-MouseEventInit-clientX"><code>clientX</code> of type <span class="idlMemberType">long</span>, defaulting to <code>0</code></dt><dd>
            <p>See <code>clientY</code> (substituting "horizontal" for "vertical").</p>
          </dd><dt id="widl-MouseEventInit-clientY"><code>clientY</code> of type <span class="idlMemberType">long</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>clientY</code> attribute of the MouseEvent
              object to the desired vertical position of the mouse pointer
              relative to the client window of the user's browser.
              </p>

            <p>Initializing the event object to the given mouse position must
              not move the user's mouse pointer to the initialized position.
              </p>
          </dd><dt id="widl-MouseEventInit-relatedTarget"><code>relatedTarget</code> of type <span class="idlMemberType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></span>, nullable, defaulting to <code>null</code></dt><dd>
            <p>The <code>relatedTarget</code> should be initialized to the element
              whose bounds the mouse pointer just left (in the case of a
              <em>mouseover</em> or <em>mouseenter</em> event) or the element
              whose bounds the mouse pointer is entering (in the case of a
              <em>mouseout</em> or <em>mouseleave</em>
              or <em>focusout</em> event). For other events, this value need not
              be assigned (and will default to null).
              </p>
          </dd><dt id="widl-MouseEventInit-screenX"><code>screenX</code> of type <span class="idlMemberType">long</span>, defaulting to <code>0</code></dt><dd>
            <p>See <code>screenY</code> (substituting "horizontal" for "veritcal").</p>
          </dd><dt id="widl-MouseEventInit-screenY"><code>screenY</code> of type <span class="idlMemberType">long</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>screenY</code> attribute of the MouseEvent
              object to the desired vertical relative position of the mouse
              pointer on the user's screen.
              </p>

            <p>Initializing the event object to the given mouse position must
              not move the user's mouse pointer to the initialized position.
              </p>
          </dd></dl></section>

      </section>  <!-- interface-MouseEvent -->

      <p id="current-click-count">Implementations <em title="MUST" class="rfc2119">MUST</em> maintain the <em>current click count</em> when generating mouse events. This <em title="MUST" class="rfc2119">MUST</em> be a non-negative integer indicating
        the number of consecutive clicks of a pointing device button within a specific time. The delay after which the count resets is specific to the
        environment configuration.</p>

      <section property="bibo:hasPart" resource="#event-modifier-initializers" typeof="bibo:Chapter" id="event-modifier-initializers">
        <h4 resource="#h-event-modifier-initializers" id="h-event-modifier-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.2 </span>Event Modifier Initializers</span></h4>

        <p>The <a href="#interface-MouseEvent"><code>MouseEvent</code></a> and
          <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> interfaces share a set
          of keyboard modifier attributes and support a mechanism for retrieving additional modifier
          states. The following dictionary enables authors to initialize keyboard modifier
          attributes of the <a href="#interface-MouseEvent"><code>MouseEvent</code></a> and
          <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> interfaces, as well as
          the additional modifier states queried via
          <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>.
          The steps for constructing events using this dictionary are defined in the
          <a href="#event-constructors">event constructors</a> section.</p>

        <pre class="idl"><span class="idlDictionary" id="idl-def-EventModifierInit">dictionary <span class="idlDictionaryID">EventModifierInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEventInit"><code>UIEventInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-ctrlKey">ctrlKey</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-shiftKey">shiftKey</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-altKey">altKey</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-metaKey">metaKey</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierAltGraph">modifierAltGraph</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierCapsLock">modifierCapsLock</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierFn">modifierFn</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierFnLock">modifierFnLock</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierHyper">modifierHyper</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierNumLock">modifierNumLock</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierOS">modifierOS</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierScrollLock">modifierScrollLock</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierSuper">modifierSuper</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierSymbol">modifierSymbol</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span> <span class="idlMemberName"><a href="#widl-EventModifierInit-modifierSymbolLock">modifierSymbolLock</a></span> = <span class="idlMemberValue">false</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-eventmodifierinit-members" typeof="bibo:Chapter" id="dictionary-eventmodifierinit-members"><h5 resource="#h-dictionary-eventmodifierinit-members" id="h-dictionary-eventmodifierinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.2.1 </span>Dictionary <a href="#idl-def-EventModifierInit" class="idlType"><code>EventModifierInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-EventModifierInit-altKey"><code>altKey</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>altKey</code> attribute of the
              <a href="#interface-MouseEvent"><code>MouseEvent</code></a> or
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
              objects to <code>true</code> if the <code title="Key Value" class="key">'Alt'</code>
              (alternative) (or <code title="Character Value Glyph" class="glyph">'Option'</code>) key modifier
              is to be considered active, <code>false</code> otherwise.</p>
            <p>When <code>true</code>, implementations must also initialize the event object's key modifier
              state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Alt'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-ctrlKey"><code>ctrlKey</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>altKey</code> attribute of the
              <a href="#interface-MouseEvent"><code>MouseEvent</code></a> or
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
              objects to <code>true</code> if the <code title="Key Value" class="key">'Control'</code>
              (control) key modifier is to be considered active,
              <code>false</code> otherwise.</p>
            <p>When <code>true</code>, implementations must also initialize the event object's key modifier
              state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with either the parameter <code title="Key Value" class="key">'Control'</code> or
              the parameter <code title="Key Value" class="key">'Accel'</code> must return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-metaKey"><code>metaKey</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>metaKey</code> attribute of the
              <a href="#interface-MouseEvent"><code>MouseEvent</code></a> or
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
              objects to <code>true</code> if the <code title="Key Value" class="key">'Meta'</code>
              key modifier is to be considered active, <code>false</code> otherwise.</p>
            <p>When <code>true</code>, implementations must also initialize the event object's
              key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with either the parameter <code title="Key Value" class="key">'Meta'</code> or
              the parameter <code title="Key Value" class="key">'Accel'</code> must return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierAltGraph"><code>modifierAltGraph</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'AltGraph'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierCapsLock"><code>modifierCapsLock</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'CapsLock'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierFn"><code>modifierFn</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Fn'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierFnLock"><code>modifierFnLock</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'FnLock'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierHyper"><code>modifierHyper</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Hyper'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierNumLock"><code>modifierNumLock</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'NumLock'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierOS"><code>modifierOS</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'OS'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierScrollLock"><code>modifierScrollLock</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'ScrollLock'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierSuper"><code>modifierSuper</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Super'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierSymbol"><code>modifierSymbol</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Symbol'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-modifierSymbolLock"><code>modifierSymbolLock</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the event object's key modifier state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'SymbolLock'</code> must
              return <code>true</code>.</p>
          </dd><dt id="widl-EventModifierInit-shiftKey"><code>shiftKey</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>shiftKey</code> attribute of the
              <a href="#interface-MouseEvent"><code>MouseEvent</code></a> or
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
              objects to <code>true</code> if the <code title="Key Value" class="key">'Shift'</code>
              key modifier is to be considered active, <code>false</code> otherwise.</p>
            <p>When <code>true</code>, implementations must also initialize the event object's key modifier
              state such that calls to the
              <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a> or
              <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState()</code></a>
              when provided with the parameter <code title="Key Value" class="key">'Shift'</code> must
              return <code>true</code>.</p>
          </dd></dl></section> <!-- END dictionary EventModifierInit defs -->
      </section> <!-- event-modifier-initializers -->

      <section property="bibo:hasPart" resource="#events-mouseevent-event-order" typeof="bibo:Chapter" id="events-mouseevent-event-order">
        <h4 resource="#h-events-mouseevent-event-order" id="h-events-mouseevent-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.3.3 </span>Mouse Event Order</span></h4>

        <p>Certain mouse events defined in this specification <em title="MUST" class="rfc2119">MUST</em> occur in a set order relative to one another.
          The following shows the event sequence that <em title="MUST" class="rfc2119">MUST</em> occur when a pointing
          device's cursor is moved over an element:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th class="cell-center">Element</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center"></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved into element A...</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center">A</td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved out of element A...</em></td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
        </tbody></table>

        <p>When a pointing device is moved into an element <em>A</em>, and then into a nested element <em>B</em>
          and then back out again, the following sequence of events <em title="MUST" class="rfc2119">MUST</em> occur:
          </p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th class="cell-center">Element</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center"></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved into element A...</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center">A</td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved into nested element B...</em></td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">7.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">8.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center">B</td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved from element B into A...</em></td>
          </tr>
          <tr>
            <td class="cell-number">9.</td>
            <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">10.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">11.</td>
            <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">12.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center">A</td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved out of element A...</em></td>
          </tr>
          <tr>
            <td class="cell-number">13.</td>
            <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">14.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
        </tbody></table>

        <p>Sometimes elements can be visually overlapped using CSS. In the following example, three elements
          labeled A, B, and C all have the same dimensions and absolute position on a web page.
          Element C is a child of B, and B is a child of A in the DOM:
          </p>

        <figure id="figure-mouse-event-stacked-elements">
          <img src="stacked-event-mouse-dispatch.svg" alt="Graphical representation of three stacked elements all on top of each other. The bottom element is labeled A and the top element is C" height="250">
          <figcaption>Fig. <span class="figno">3</span> <span class="fig-title">Graphical representation of three stacked elements all on top of each other, with the pointing device moving over the stack.</span></figcaption>
        </figure>

        <p>When the pointing device is moved from outside the element stack to the element labeled C and then moved
          out again, the following series of events <em title="MUST" class="rfc2119">MUST</em> occur:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th class="cell-center">Element</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center"></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved into element C, the topmost element in the stack</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></td>
            <td class="cell-center">C</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></td>
            <td class="cell-center">C</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td class="cell-center">C</td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>Pointing device is moved out of element C...</em></td>
          </tr>
          <tr>
            <td class="cell-number">7.</td>
            <td><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></td>
            <td class="cell-center">C</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">8.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">C</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">9.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">B</td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">10.</td>
            <td><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></td>
            <td class="cell-center">A</td>
            <td></td>
          </tr>
        </tbody></table>

        <div class="note"><div id="h-note26" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <code>mouseover</code>/<code>mouseout</code> events are only fired once, while <code>mouseenter</code>/<code>mouseleave</code>
          events are fired three times (once to each element).</p></div>

        <p>The following is the typical sequence of events when a button associated with a pointing device (e.g., a mouse button or trackpad) is pressed and released over
          an element:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td><em title="OPTIONAL" class="rfc2119">OPTIONAL</em>, multiple events, some limits</td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td><em title="OPTIONAL" class="rfc2119">OPTIONAL</em>, multiple events, some limits</td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">7.</td>
            <td><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></td>
            <td><em title="OPTIONAL" class="rfc2119">OPTIONAL</em>, multiple events, some limits</td>
          </tr>
          <tr>
            <td class="cell-number">8.</td>
            <td><a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">9.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">10.</td>
            <td><a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a></td>
            <td></td>
          </tr>
        </tbody></table>

        <div class="note"><div id="h-note27" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>The lag time, degree, distance, and number of <a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a>
          events allowed between the <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> and <a class="eventtype" href="#event-type-mouseup">
          <code>mouseup</code></a> events while still firing a <a class="eventtype" href="#event-type-click"><code>click</code></a> or <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> event will be implementation-, device-, and platform-specific. This tolerance can aid users that have physical
          disabilities like unsteady hands when these users interact with a pointing device.</p></div>

        <p>Each implementation will determine the appropriate <a class="def" href="#glossary-hysteresis">hysteresis</a>
          tolerance, but in general <em title="SHOULD" class="rfc2119">SHOULD</em> fire <a class="eventtype" href="#event-type-click"><code>click</code></a>
          and <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> events when the event target
          of the associated <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> and
          <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> events is the same element with no
          <a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a> or
          <a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a> events intervening, and <em title="SHOULD" class="rfc2119">SHOULD</em>
          fire <a class="eventtype" href="#event-type-click"><code>click</code></a> and
          <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> events on the nearest common inclusive
          ancestor when the associated <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> and
          <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> event targets are different.</p>

        <div class="example">
          <div class="example-title"></div>
          <p>If a <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> event was targeted at an
          HTML document's <a href="#glossary-body-element">body element</a>, and the corresponding
          <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> event was targeted at the
          <a href="#glossary-root-element">root element</a>, then the
          <a class="eventtype" href="#event-type-click"><code>click</code></a> event will be dispatched to the
          <a href="#glossary-root-element">root element</a>, since it is the nearest common inclusive ancestor.</p>
        </div>

        <p>If the <a class="def" href="#glossary-event-target">event target</a> (e.g. the target element) is removed from the DOM during the mouse events sequence, the remaining
          events of the sequence <em title="MUST NOT" class="rfc2119">MUST NOT</em> be fired on that element.</p>

        <div class="example">
          <div class="example-title"></div>
          <p>If the target element is removed from the DOM as the result of a <a class="eventtype" href="#event-type-mousedown">
          <code>mousedown</code></a> event, no events for that element will be dispatched for <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>,
          <a class="eventtype" href="#event-type-click"><code>click</code></a>, or <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a>, nor any default
          activation events. However, the <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> event will still be dispatched on the element that is exposed
          to the mouse after the removal of the initial target element. Similarly, if the target element is removed from the DOM during the dispatch of a <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> event, the <a class="eventtype" href="#event-type-click"><code>click</code></a> and subsequent events will
          not be dispatched.</p>
        </div>

      </section>  <!-- events-mouseevent-event-order -->

      <p>The Mouse event types are listed below. In the case of nested elements, mouse event types are always targeted at the most deeply nested element. Ancestors of the
        targeted element <em title="MAY" class="rfc2119">MAY</em> use bubbling to obtain notification of mouse events which occur within its descendent elements.</p>

      <!-- click -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-click"><dfn id="dfn-click"><a class="eventtype" href="#event-type-click"><code>click</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>click</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Varies</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      indicates the <a href="#current-click-count">current click count</a>;
                      the attribute value <em title="MUST" class="rfc2119">MUST</em> be <code>1</code> when the user begins this action and increments by <code>1</code> for each click.</li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      value based on current button pressed</li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>The <a class="eventtype" href="#event-type-click"><code>click</code></a> event type <em title="MUST" class="rfc2119">MUST</em> be dispatched on the
              <a class="def" href="#glossary-topmost-event-target">topmost event target</a> indicated by the pointer, when
              the user presses down and releases the primary pointer button,
              or otherwise activates the pointer in a manner that simulates such an action.
              The actuation method of the mouse button depends upon the pointer device and the environment configuration,
              e.g., it <em title="MAY" class="rfc2119">MAY</em> depend on the screen location or the delay between the press and release of the pointing device button.
              </p>

            <p>The <code>click</code> event should only be fired for the primary
              pointer button (i.e., when <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a> value is <code>0</code>,
              <a href="#widl-MouseEvent-buttons"><code>MouseEvent.buttons</code></a> value is <code>1</code>).
              Secondary buttons (like the middle or right button on a standard mouse) <em title="MUST NOT" class="rfc2119">MUST NOT</em> fire
              <code>click</code> events.
              </p>

            <p>The <a class="eventtype" href="#event-type-click"><code>click</code></a> event <em title="MAY" class="rfc2119">MAY</em> be preceded by the <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a>
              and <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> events on the same element, disregarding changes between other node types (e.g., text
              nodes).  Depending upon the environment configuration, the <a class="eventtype" href="#event-type-click"><code>click</code></a> event <em title="MAY" class="rfc2119">MAY</em> be dispatched if one or
              more of the event types <a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a>, <a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a>,
              and <a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a> occur between the press and release of the pointing device button.  The <a class="eventtype" href="#event-type-click"><code>click</code></a> event <em title="MAY" class="rfc2119">MAY</em> also be followed by the <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a>
              event.</p>

            <div class="example">
              <div class="example-title"></div>
              <p>If a user mouses down on a text node child of a <code>&lt;p&gt;</code> element which has been styled with
                a large line-height, shifts the mouse slightly such that it is no longer over an area containing text but is still within the containing block of that <code>&lt;p&gt;</code>
                element (i.e., the pointer is between lines of the same text block, but not over the text node per se), then subsequently mouses up, this will likely still trigger
                a <a class="eventtype" href="#event-type-click"><code>click</code></a> event (if it falls within the normal temporal <a class="def" href="#glossary-hysteresis">hysteresis</a> for a <a class="eventtype" href="#event-type-click">
                <code>click</code></a>), since the user has stayed within the scope of the same element. Note that user-agent-generated mouse events are not dispatched on text nodes.
              </p>
            </div>

            <p>In addition to being associated with pointer devices, the <a class="eventtype" href="#event-type-click"><code>click</code></a> event type <em title="MUST" class="rfc2119">MUST</em> be dispatched as
              part of an element activation, as described in <a href="#event-flow-activation">Activation triggers and behavior</a>.</p>

            <div class="note"><div id="h-note28" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> For maximum accessibility, content authors are encouraged to use the
              <a class="eventtype" href="#event-type-click"><code>click</code></a> event type when defining activation
              behavior for custom controls, rather than other pointing-device event types such as
              <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> or
              <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>, which are more device-specific.
              Though the <a class="eventtype" href="#event-type-click"><code>click</code></a> event type has its origins
              in pointer devices (e.g., a mouse), subsequent implementation
              enhancements have extended it beyond that association, and it can be considered a device-independent event
              type for element activation.
              </p></div>

            <p>The <a class="def" href="#glossary-default-action">default action</a> of the
              <a class="eventtype" href="#event-type-click"><code>click</code></a> event type varies
              based on the <a class="def" href="#glossary-event-target">event target</a> of the event and the value of the
              <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a>
              or <a href="#widl-MouseEvent-buttons"><code>MouseEvent.buttons</code></a> attributes.
              Typical <a class="def" href="#glossary-default-action">default actions</a>
              of the <a class="eventtype" href="#event-type-click"><code>click</code></a> event type are as follows:
              </p>

            <ul>
              <li>If the <a class="def" href="#glossary-event-target">event target</a> has associated activation behavior, the <a class="def" href="#glossary-default-action">default
                action</a> <em title="MUST" class="rfc2119">MUST</em> be to execute that activation behavior (see <a href="#event-flow-activation">Activation triggers and behavior</a>).</li>

              <li>If the <a class="def" href="#glossary-event-target">event target</a> is focusable, the <a class="def" href="#glossary-default-action">default action</a> <em title="MUST" class="rfc2119">MUST</em> be
                to give that element document focus.</li>
            </ul>
          </dd>
        </dl>
      </div>

      <!-- dblclick -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-dblclick"><dfn id="dfn-dblclick"><a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>dblclick</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      indicates the <a href="#current-click-count">current click count</a></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      value based on current button pressed</li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when the primary button
              of a pointing device is clicked twice over an element. The definition of a double click depends on the environment
              configuration, except that the event target <em title="MUST" class="rfc2119">MUST</em> be the same between
              <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a>,
              <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>, and
              <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a>.
              This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the event type
              <a class="eventtype" href="#event-type-click"><code>click</code></a>
              if a click and double click occur simultaneously,
              and after the event type <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> otherwise.
              </p>

            <p>As with the <code>click</code> event, the <code>dblclick</code> event
              should only be fired for the primary pointer button.
              Secondary buttons <em title="MUST NOT" class="rfc2119">MUST NOT</em> fire <code>dblclick</code> events.
              </p>

            <div class="note"><div id="h-note29" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Canceling the
              <a class="eventtype" href="#event-type-click"><code>click</code></a> event does not affect the firing
              of a <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> event.
              </p></div>

            <p>As with the <a class="eventtype" href="#event-type-click"><code>click</code></a> event type, the
              <a class="def" href="#glossary-default-action">default action</a>
              of the <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> event type varies based on the
              <a class="def" href="#glossary-event-target">event target</a> of the event and the value of the
              <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a> or
              <a href="#widl-MouseEvent-buttons"><code>MouseEvent.buttons</code></a> attributes.
              Normally, the typical <a class="def" href="#glossary-default-action">default actions</a> of the
              <a class="eventtype" href="#event-type-dblclick"><code>dblclick</code></a> event type match those of the
              <a class="eventtype" href="#event-type-click"><code>click</code></a> event type, with the following additional
              behavior:
              </p>

            <ul>
              <li>If the <a class="def" href="#glossary-event-target">event target</a> is selectable, the <a class="def" href="#glossary-default-action">default action</a> <em title="MUST" class="rfc2119">MUST</em>
                be to select part or all of the selectable content. Subsequent clicks <em title="MAY" class="rfc2119">MAY</em> select additional selectable portions of that content.</li>
            </ul>
          </dd>
        </dl>
      </div>

      <!-- mousedown -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mousedown"><dfn id="dfn-mousedown"><a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mousedown</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Varies: Start a drag/drop operation; start a text selection; start a scroll/pan interaction (in combination with the middle mouse button, if supported)</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      indicates the <a href="#current-click-count">current click count</a> incremented by one. For example, if no click happened
                      before the <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a>, <a href="#widl-UIEvent-detail"><code>UIEvent.detail</code></a>
                      will contain the value <code>1</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      value based on current button pressed</li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device button is pressed over an element.</p>

            <div class="note"><div id="h-note30" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>Many implementations use the <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a> event to begin a variety of contextually dependent <a class="def" href="#glossary-default-action">default actions</a>. These default actions can be prevented if this event is canceled. Some of these default actions could include: beginning
              a drag/drop interaction with an image or link, starting text selection, etc. Additionally, some implementations provide a mouse-driven panning feature that is activated when
              the middle mouse button is pressed at the time the <a href="#dfn-mousedown" class="eventtype internalDFN"><code>mousedown</code></a> event is dispatched.</p></div>

          </dd>
        </dl>
      </div>

      <!-- mouseenter -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mouseenter"><dfn id="dfn-mouseenter"><a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mouseenter</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      indicates the <a class="def" href="#glossary-event-target">event target</a> a pointing device is exiting, if any.</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device is moved onto the boundaries of an element or one of
              its descendent elements.  This event type is similar to <a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a>, but differs in that it does
              not bubble, and <em title="MUST NOT" class="rfc2119">MUST NOT</em> be dispatched when the pointer device moves from an element onto the boundaries of one of its descendent elements.</p>

            <div class="note"><div id="h-note31" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> There are similarities between this event type and the CSS <a href="http://www.w3.org/TR/CSS2/selector.html#dynamic-pseudo-classes" title="Selectors"><code>:hover</code> pseudo-class</a> <a href="#references-CSS2">[CSS2.1]</a>.  See also the <a class="eventtype" href="#event-type-mouseleave"><code>
              mouseleave</code></a> event type.</p></div>

          </dd>
        </dl>
      </div>

      <!-- mouseleave -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mouseleave"><dfn id="dfn-mouseleave"><a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mouseleave</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      indicates the <a class="def" href="#glossary-event-target">event target</a> a pointing device is entering, if any.</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>
            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device is moved off of the boundaries of an element and all
              of its descendent elements.  This event type is similar to <a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a>, but differs in that does
              not bubble, and that it <em title="MUST NOT" class="rfc2119">MUST NOT</em> be dispatched until the pointing device has left the boundaries of the element and the boundaries of all of its children.</p>

            <div class="note"><div id="h-note32" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> There are similarities between this event type and the CSS <a href="http://www.w3.org/TR/CSS2/selector.html#dynamic-pseudo-classes" title="Selectors"><code>:hover</code> pseudo-class</a> <a href="#references-CSS2">[CSS2.1]</a>.  See also the <a class="eventtype" href="#event-type-mouseenter"><code>
              mouseenter</code></a> event type.</p></div>
          </dd>
        </dl>
      </div>

      <!-- mousemove -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mousemove"><dfn id="dfn-mousemove"><a class="eventtype" href="#event-type-mousemove"><code>mousemove</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mousemove</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device is moved while it is over an element.  The frequency
              rate of events while the pointing device is moved is implementation-, device-, and platform-specific, but multiple consecutive <a class="eventtype" href="#event-type-mousemove">
              <code>mousemove</code></a> events <em title="SHOULD" class="rfc2119">SHOULD</em> be fired for sustained pointer-device movement, rather than a single event for each instance of mouse movement.  Implementations
              are encouraged to determine the optimal frequency rate to balance responsiveness with performance.
              </p>

            <div class="note"><div id="h-note33" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note: </strong>In some implementation environments, such as a browser, <a href="#dfn-mousemove" class="eventtype internalDFN"><code>mousemove</code></a> events can continue
              to fire if the user began a drag operation (e.g., a mouse button is pressed) and the pointing device has left the boundary of the user agent.
              </p></div>

            <div class="note"><div id="h-note34" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="mousemove-now-cancelable"><strong>Note: </strong>This event was formerly specified to be non-cancelable in DOM Level 2 Events
              [<a href="#references-DOM2Events">DOM2 Events</a>], but was changed to reflect existing interoperability between
              user agents.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- mouseout -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mouseout"><dfn id="dfn-mouseout"><a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mouseout</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      indicates the <a class="def" href="#glossary-event-target">event target</a> a pointing device is entering, if any.</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device is moved off of the boundaries of an element.  This
              event type is similar to <a class="eventtype" href="#event-type-mouseleave"><code>mouseleave</code></a>, but differs in that does bubble, and that it <em title="MUST" class="rfc2119">MUST</em> be dispatched
              when the pointer device moves from an element onto the boundaries of one of its descendent elements.</p>

            <div class="note"><div id="h-note35" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> See also the <a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a> event type.</p></div>
          </dd>
        </dl>
      </div>

      <!-- mouseover -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mouseover"><dfn id="dfn-mouseover"><a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody>
                <tr>
                  <th>Type</th>
                  <td><strong><code>mouseover</code></strong></td>
                </tr>
                <tr>
                  <th>Interface</th>
                  <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
                </tr>
                <tr>
                  <th>Sync / Async</th>
                  <td>Sync</td>
                </tr>
                <tr>
                  <th>Bubbles</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Trusted Targets</th>
                  <td><code>Element</code></td>
                </tr>
                <tr>
                  <th>Cancelable</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Default action</th>
                  <td>None</td>
                </tr>
                <tr>
                  <th>Context<br>(trusted events)</th>
                  <td>
                    <ul>
                      <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                        <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                      <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                        <a class="def" href="#glossary-window"><code>Window</code></a></li>
                      <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                        <code>0</code></li>
                      <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                        value based on the pointer position on the screen</li>
                      <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                        value based on the pointer position on the screen</li>
                      <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                        value based on the pointer position within the viewport</li>
                      <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                        value based on the pointer position within the viewport</li>
                      <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                        <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                      <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                        <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                      <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                        <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                      <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                        <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                      <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                        <code>0</code></li>
                      <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                        value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                      <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                        indicates the <a class="def" href="#glossary-event-target">event target</a> a pointing device is exiting, if any.</li>
                    </ul>
                  </td>
                </tr>
              </tbody>
            </table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device is moved onto the boundaries of an element.  This event
              type is similar to <a class="eventtype" href="#event-type-mouseenter"><code>mouseenter</code></a>, but differs in that it bubbles, and that it <em title="MUST" class="rfc2119">MUST</em> be dispatched
              when the pointer device moves onto the boundaries of an element whose ancestor element is the <a class="def" href="#glossary-event-target">event target</a> for
              the same event listener instance.</p>

            <div class="note"><div id="h-note36" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> See also the <a class="eventtype" href="#event-type-mouseout"><code>mouseout</code></a> event type.</p></div>
          </dd>
        </dl>
      </div>

      <!-- mouseup -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-mouseup"><dfn id="dfn-mouseup"><a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>mouseup</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MouseEvent"><code>MouseEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Invoke a context menu (in combination with the right mouse button, if supported)</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      indicates the <a href="#current-click-count">current click count</a> incremented by one.</li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      value based on the pointer position on the screen</li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      value based on the pointer position within the viewport</li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      value based on current button pressed</li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a pointing device button is released over an element.</p>

            <div class="note"><div id="h-note37" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>Many implementations will invoke a context menu as the default action of this event if the right mouse button is being released.</p></div>

            <div class="note"><div id="h-note38" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note: </strong>In some implementation environments,
              such as a browser, a <a href="#dfn-mouseup" class="eventtype internalDFN"><code>mouseup</code></a> event
              can be dispatched even if the pointing device has left the boundary of the user
              agent, e.g., if the user began a drag operation with a mouse button pressed.</p></div>
          </dd>
        </dl>
      </div>
    </section>  <!-- events-mouseevents -->

    <section property="bibo:hasPart" resource="#events-wheelevents" typeof="bibo:Chapter" id="events-wheelevents">
      <h3 resource="#h-events-wheelevents" id="h-events-wheelevents"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.4 </span>Wheel Event Types</span></h3>
      <p>Wheels are devices that can be rotated in one or more spatial dimensions, and which can be associated with a pointer device. The coordinate system depends on the
        environment configuration.</p>

      <div class="example">
        <div class="example-title"></div>
        <p>The user's environment might be configured to associate vertical scrolling
          with rotation along the y-axis, horizontal scrolling with rotation along
          the x-axis, and zooming with rotation along the z-axis.
          </p>
      </div>

      <p>The deltaX, deltaY, and deltaZ attributes of
        <a href="#interface-WheelEvent"><code>WheelEvent</code></a> objects indicate a
        measurement along their respective axes in units of pixels, lines, or pages.
        The reported measurements are provided after an environment-specific algorithm
        translates the actual rotation/movement of the wheel device into the appropriate
        values and units.
        </p>

      <div class="note"><div id="h-note39" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
        A user's environment settings can be customized to interpret actual rotation/movement
        of a wheel device in different ways.
        One movement of a common <q>dented</q> mouse wheel can produce a measurement of 162 pixels
        (162 is just an example value, actual values can depend on the current screen
        dimensions of the user-agent).
        But a user can change their default environment settings to speed-up their mouse wheel,
        increasing this number.
        Furthermore, some mouse wheel software can support acceleration (the faster the wheel
        is rotated/moved, the greater the <a class="def" href="#glossary-delta">delta</a> of each measurement) or even sub-pixel <a class="def" href="#glossary-rotation">rotation</a>
        measurements.
        Because of this, authors can not assume a given <a class="def" href="#glossary-rotation">rotation</a> amount in one user agent will
        produce the same <a class="def" href="#glossary-delta">delta</a> value in all user agents.
        </p></div>

      <p>The sign (positive or negative) of the values of the deltaX, deltaY, and deltaZ attributes
        <em title="MUST" class="rfc2119">MUST</em> be consistent between multiple dispatches of the
        <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event while the
        motion of the actual wheel device is rotating/moving in the same direction.
        If a user agent scrolls as the default action of the
        <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event then the sign
        of the <a class="def" href="#glossary-delta">delta</a> <em title="SHOULD" class="rfc2119">SHOULD</em> be given by a right-hand coordinate system where positive X,
        Y, and Z axes are directed towards the right-most edge, bottom-most edge, and farthest
        depth (away from the user) of the document, respectively.
        </p>

      <div class="note"><div id="h-note40" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        Individual user agents can (depending on their environment and hardware configuration)
        interpret the same physical user interaction on the wheel differently.
        For example, a vertical swipe on the edge of a trackpad from top to bottom can be
        interpreted as a wheel action intended to either scroll the
        page down or to pan the page up (i.e., resulting in either a positive or negative
        deltaY value respectively).
        </p></div>

      <section property="bibo:hasPart" resource="#interface-WheelEvent" typeof="bibo:Chapter" id="interface-WheelEvent">
        <h4 resource="#h-interface-wheelevent" id="h-interface-wheelevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.4.1 </span>Interface WheelEvent</span></h4>

        <p class="intro-dom">Introduced in this specification</p>

        <p>The <code>WheelEvent</code> interface provides specific contextual information
          associated with <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a>
          events.
          </p>

        <p>To create an instance of the <code>WheelEvent</code> interface, use the
          <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("WheelEvent")</code></a>
          method call.
          </p>

        <pre class="idl"><span class="idlInterface" id="idl-def-WheelEvent">[<span class="extAttr">Constructor(DOMString typeArg, optional WheelEventInit wheelEventInitDict)</span>]
interface <span class="idlInterfaceID">WheelEvent</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-MouseEvent"><code>MouseEvent</code></a></span> {
<span class="idlSectionComment">    // DeltaModeCode</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-WheelEvent-DOM_DELTA_PIXEL">DOM_DELTA_PIXEL</a></span> = <span class="idlConstValue">0x00</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-WheelEvent-DOM_DELTA_LINE">DOM_DELTA_LINE</a></span> = <span class="idlConstValue">0x01</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-WheelEvent-DOM_DELTA_PAGE">DOM_DELTA_PAGE</a></span> = <span class="idlConstValue">0x02</span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">double</span>        <span class="idlAttrName"><a href="#widl-WheelEvent-deltaX">deltaX</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">double</span>        <span class="idlAttrName"><a href="#widl-WheelEvent-deltaY">deltaY</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">double</span>        <span class="idlAttrName"><a href="#widl-WheelEvent-deltaZ">deltaZ</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned long</span> <span class="idlAttrName"><a href="#widl-WheelEvent-deltaMode">deltaMode</a></span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-3" typeof="bibo:Chapter" id="attributes-3"><h5 resource="#h-attributes-3" id="h-attributes-3"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.4.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-WheelEvent-deltaMode"><code>deltaMode</code> of type <span class="idlAttrType">unsigned long</span>, readonly   </dt><dd>
            <p>The <code>deltaMode</code> attribute contains an indication of the units of measurement for the
              <a href="#glossary-delta">delta</a> values.
              The default value is
                <a href="#widl-WheelEvent-DOM_DELTA_PIXEL"><code class="constant-name">DOM_DELTA_PIXEL</code></a>
              (pixels).
              </p>

            <p>This attribute <em title="MUST" class="rfc2119">MUST</em> be set to one of the DOM_DELTA constants to indicate the units of measurement
              for the <a href="#glossary-delta">delta</a> values.  The precise measurement
              is specific to device, operating system, and application configurations.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute
              <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>
          </dd><dt id="widl-WheelEvent-deltaX"><code>deltaX</code> of type <span class="idlAttrType">double</span>, readonly   </dt><dd>
            <p>In user agents where the default action of the
              <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event is to scroll,
              the value <em title="MUST" class="rfc2119">MUST</em> be the measurement along the x-axis (in pixels, lines, or pages) to be scrolled
              in the case where the event is not cancelled. Otherwise, this is an implementation-specific
              measurement (in pixels, lines, or pages) of the movement of a wheel device around the x-axis.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute
              <em title="MUST" class="rfc2119">MUST</em> be <code>0.0</code>.
              </p>
          </dd><dt id="widl-WheelEvent-deltaY"><code>deltaY</code> of type <span class="idlAttrType">double</span>, readonly   </dt><dd>
            <p>In user agents where the default action of the
              <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event is to scroll, the value
              <em title="MUST" class="rfc2119">MUST</em> be the measurement along the y-axis (in pixels, lines, or pages) to be scrolled in the case
              where the event is not cancelled. Otherwise, this is an implementation-specific
              measurement (in pixels, lines, or pages) of the movement of a wheel device around the y-axis.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute
              <em title="MUST" class="rfc2119">MUST</em> be <code>0.0</code>.
              </p>
          </dd><dt id="widl-WheelEvent-deltaZ"><code>deltaZ</code> of type <span class="idlAttrType">double</span>, readonly   </dt><dd>
            <p>In user agents where the default action of the
              <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event is to scroll, the value
              <em title="MUST" class="rfc2119">MUST</em> be the measurement along the z-axis (in pixels, lines, or pages) to be scrolled in the case
              where the event is not cancelled. Otherwise, this is an implementation-specific
              measurement (in pixels, lines, or pages) of the movement of a wheel device around the z-axis.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute
              <em title="MUST" class="rfc2119">MUST</em> be <code>0.0</code>.
              </p>
          </dd></dl></section><section property="bibo:hasPart" resource="#constants" typeof="bibo:Chapter" id="constants"><h5 resource="#h-constants" id="h-constants"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.4.1.2 </span>Constants</span></h5><dl class="constants"><dt id="widl-WheelEvent-DOM_DELTA_LINE"><code>DOM_DELTA_LINE</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The units of measurement for the <a href="#glossary-delta">delta</a> <em title="MUST" class="rfc2119">MUST</em> be
              individual lines of text.  This is the case for many form controls.
              </p>
          </dd><dt id="widl-WheelEvent-DOM_DELTA_PAGE"><code>DOM_DELTA_PAGE</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The units of measurement for the <a href="#glossary-delta">delta</a> <em title="MUST" class="rfc2119">MUST</em> be
              pages, either defined as a single screen or as a demarcated page.
              </p>
          </dd><dt id="widl-WheelEvent-DOM_DELTA_PIXEL"><code>DOM_DELTA_PIXEL</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The units of measurement for the <a href="#glossary-delta">delta</a> <em title="MUST" class="rfc2119">MUST</em> be
              pixels. This is the most typical case in most operating system and implementation
              configurations.
              </p>
          </dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-WheelEventInit">dictionary <span class="idlDictionaryID">WheelEventInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-MouseEventInit"><code>MouseEventInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType">double</span>        <span class="idlMemberName"><a href="#widl-WheelEventInit-deltaX">deltaX</a></span> = <span class="idlMemberValue">0.0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">double</span>        <span class="idlMemberName"><a href="#widl-WheelEventInit-deltaY">deltaY</a></span> = <span class="idlMemberValue">0.0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">double</span>        <span class="idlMemberName"><a href="#widl-WheelEventInit-deltaZ">deltaZ</a></span> = <span class="idlMemberValue">0.0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">unsigned long</span> <span class="idlMemberName"><a href="#widl-WheelEventInit-deltaMode">deltaMode</a></span> = <span class="idlMemberValue">0</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-wheeleventinit-members" typeof="bibo:Chapter" id="dictionary-wheeleventinit-members"><h5 resource="#h-dictionary-wheeleventinit-members" id="h-dictionary-wheeleventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.4.1.3 </span>Dictionary <a href="#idl-def-WheelEventInit" class="idlType"><code>WheelEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-WheelEventInit-deltaMode"><code>deltaMode</code> of type <span class="idlMemberType">unsigned long</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>deltaMode</code> attribute on the WheelEvent
              object to the enumerated values 0, 1, or 2, which represent the amount
              of pixels scrolled
              (<a href="#widl-WheelEvent-DOM_DELTA_PIXEL"><code class="constant-name">DOM_DELTA_PIXEL</code></a>),
              lines scrolled
              (<a href="#widl-WheelEvent-DOM_DELTA_LINE"><code class="constant-name">DOM_DELTA_LINE</code></a>),
              or pages scrolled
              (<a href="#widl-WheelEvent-DOM_DELTA_PAGE"><code class="constant-name">DOM_DELTA_PAGE</code></a>)
              if the <a class="def" href="#glossary-rotation">rotation</a> of the wheel would
              have resulted in scrolling.
              </p>
          </dd><dt id="widl-WheelEventInit-deltaX"><code>deltaX</code> of type <span class="idlMemberType">double</span>, defaulting to <code>0.0</code></dt><dd><p>See <code>deltaZ</code> attribute.</p></dd><dt id="widl-WheelEventInit-deltaY"><code>deltaY</code> of type <span class="idlMemberType">double</span>, defaulting to <code>0.0</code></dt><dd><p>See <code>deltaZ</code> attribute.</p></dd><dt id="widl-WheelEventInit-deltaZ"><code>deltaZ</code> of type <span class="idlMemberType">double</span>, defaulting to <code>0.0</code></dt><dd>
            <p>Initializes the <code>deltaZ</code> attribute of the WheelEvent object.
              Relative positive values for this attribute (as well as the
              <code>deltaX</code> and <code>deltaY</code> attributes) are given by
              a right-hand coordinate system where the X, Y, and Z axes are
              directed towards the right-most edge, bottom-most edge, and farthest
              depth (away from the user) of the document, respectively. Negative
              relative values are in the respective opposite directions.
              </p>
          </dd></dl></section>

      </section>  <!-- interface-WheelEvent -->

      <p>The Wheel event types are listed below.</p>

      <!-- wheel -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-wheel"><dfn id="dfn-wheel"><a class="eventtype" href="#event-type-wheel"><code>wheel</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>wheel</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-WheelEvent"><code>WheelEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Async</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Scroll (or zoom) the document</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-topmost-event-target">topmost event target</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenX"><code class="attribute-name">MouseEvent.screenX</code></a>:
                      if the wheel is associated with a pointing device, the value based on the pointer position on the screen, otherwise <code>0</code></li>
                    <li><a href="#widl-MouseEvent-screenY"><code class="attribute-name">MouseEvent.screenY</code></a>:
                      if the wheel is associated with a pointing device, the value based
                      on the pointer position on the screen, otherwise <code>0</code></li>
                    <li><a href="#widl-MouseEvent-clientX"><code class="attribute-name">MouseEvent.clientX</code></a>:
                      if the wheel is associated with a pointing device, the value based
                      on the pointer position within the viewport, otherwise <code>0</code></li>
                    <li><a href="#widl-MouseEvent-clientY"><code class="attribute-name">MouseEvent.clientY </code></a>:
                      if the wheel is associated with a pointing device, the value
                      based on the pointer position within the viewport, otherwise <code>0</code></li>
                    <li><a href="#widl-MouseEvent-altKey"><code class="attribute-name">MouseEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code>
                      modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-ctrlKey"><code class="attribute-name">MouseEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-shiftKey"><code class="attribute-name">MouseEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-metaKey"><code class="attribute-name">MouseEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-MouseEvent-button"><code class="attribute-name">MouseEvent.button</code></a>:
                      if wheel is associated with a pointing device, value based on current button pressed, otherwise <code>0</code></li>
                    <li><a href="#widl-MouseEvent-buttons"><code class="attribute-name">MouseEvent.buttons</code></a>:
                      if wheel is associated with a pointing device, value based on all buttons current depressed, <code>0</code> if no buttons pressed</li>
                    <li><a href="#widl-MouseEvent-relatedTarget"><code class="attribute-name">MouseEvent.relatedTarget</code></a>:
                      indicates the <a class="def" href="#glossary-event-target">event target</a> the pointing device is pointing at, if any.</li>
                    <li><a href="#widl-WheelEvent-deltaX"><code class="attribute-name">WheelEvent.deltaX</code></a>:
                      expected amount that the page will scroll along the x-axis according
                      to the deltaMode units; or an implemenation-specific value of movement of a wheel around the x-axis</li>
                    <li><a href="#widl-WheelEvent-deltaY"><code class="attribute-name">WheelEvent.deltaY</code></a>:
                      expected amount that the page will scroll along the y-axis according
                      to the deltaMode units; or an implemenation-specific value of movement of a wheel around the y-axis</li>
                    <li><a href="#widl-WheelEvent-deltaZ"><code class="attribute-name">WheelEvent.deltaZ</code></a>:
                      expected amount that the page will scroll along the z-axis according
                      to the deltaMode units; or an implemenation-specific value of movement of a wheel around the z-axis</li>
                    <li><a href="#widl-WheelEvent-deltaMode"><code class="attribute-name">WheelEvent.deltaMode</code></a>:
                      unit indicator (pixels, lines, or pages) for the deltaX, deltaY, and deltaZ attributes</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a mouse wheel has been rotated around any axis, or when an equivalent
              input device (such as a mouse-ball, certain tablets or touchpads, etc.) has emulated such an action. Depending on the platform and input device, diagonal wheel
              <a class="def" href="#glossary-delta">deltas</a> <em title="MAY" class="rfc2119">MAY</em> be delivered either as a single <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event with multiple non-zero axes or as separate <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a>
              events for each non-zero axis.</p>

            <p>The typical <a class="def" href="#glossary-default-action">default action</a> of the <a class="eventtype" href="#event-type-wheel"><code>wheel</code></a> event
              type is to scroll (or in some cases, zoom) the document by the indicated amount.  If this event is canceled, the implementation <em title="MUST NOT" class="rfc2119">MUST NOT</em> scroll or zoom the document
              (or perform whatever other implementation-specific default action is associated with this event type).</p>

            <div class="note"><div id="h-note41" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> In some <a class="def" href="#glossary-user-agent">user agents</a>, or with some input devices, the speed that the wheel has been
              turned can affect the <a href="#glossary-delta">delta</a> values, with a faster speed producing a higher <a href="#glossary-delta">delta</a> value.</p></div>
          </dd>
        </dl>
      </div>
    </section>  <!-- events-wheelevents -->

    <section property="bibo:hasPart" resource="#events-keyboardevents" typeof="bibo:Chapter" id="events-keyboardevents">
      <h3 resource="#h-events-keyboardevents" id="h-events-keyboardevents"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5 </span>Keyboard Event Types</span></h3>

      <p>Keyboard events are device dependent, i.e., they rely on the capabilities of the
        input devices and how they are mapped in the operating systems. Refer to
        <a href="#keys">Keyboard events and key values</a> for more details, including
        examples on how Keyboard Events are used in combination with Composition Events.
        Depending on the
        character generation device, keyboard events might not be generated.
        </p>

      <div class="note"><div id="h-note42" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
        Keyboard events are only one modality of providing textual input.
        For editing scenarios, consider also using the
          <a href="http://w3c.github.io/editing-explainer/input-events.html#idl-def-InputEvent"><code>InputEvent</code></a>
        as an alternate to (or in addition to) keyboard events.
        </p></div>

      <section property="bibo:hasPart" resource="#interface-KeyboardEvent" typeof="bibo:Chapter" id="interface-KeyboardEvent">
        <h4 resource="#h-interface-keyboardevent" id="h-interface-keyboardevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.1 </span>Interface KeyboardEvent</span></h4>

        <p class="intro-dom">Introduced in this specification</p>

        <p>The <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> interface
          provides specific contextual information associated with keyboard devices.
          Each keyboard event references a key using a value.
          Keyboard events are commonly directed at the element that has the focus.
          </p>

        <p>The <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> interface
          provides convenient attributes for some common modifiers keys:
            <a href="#widl-KeyboardEvent-ctrlKey"><code>KeyboardEvent.ctrlKey</code></a>,
            <a href="#widl-KeyboardEvent-shiftKey"><code>KeyboardEvent.shiftKey</code></a>,
            <a href="#widl-KeyboardEvent-altKey"><code>KeyboardEvent.altKey</code></a>,
            <a href="#widl-KeyboardEvent-metaKey"><code>KeyboardEvent.metaKey</code></a>.
          These attributes are equivalent to using the method
            <a href="#widl-KeyboardEvent-getModifierState"><code>KeyboardEvent.getModifierState(keyArg)</code></a>
          with
            <code title="Key Value" class="key">'Control'</code>,
            <code title="Key Value" class="key">'Shift'</code>,
            <code title="Key Value" class="key">'Alt'</code>, or
            <code title="Key Value" class="key">'Meta'</code>
          respectively.
          </p>

        <p>To create an instance of the <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
          interface, use the
            <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("KeyboardEvent")</code></a>
          method call.
          </p>

        <pre class="idl"><span class="idlInterface" id="idl-def-KeyboardEvent">[<span class="extAttr">Constructor(DOMString typeArg, optional KeyboardEventInit keyboardEventInitDict)</span>]
interface <span class="idlInterfaceID">KeyboardEvent</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEvent"><code>UIEvent</code></a></span> {
<span class="idlSectionComment">    // KeyLocationCode</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_STANDARD">DOM_KEY_LOCATION_STANDARD</a></span> = <span class="idlConstValue">0x00</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_LEFT">DOM_KEY_LOCATION_LEFT</a></span> = <span class="idlConstValue">0x01</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_RIGHT">DOM_KEY_LOCATION_RIGHT</a></span> = <span class="idlConstValue">0x02</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned long</span> <span class="idlConstName"><a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_NUMPAD">DOM_KEY_LOCATION_NUMPAD</a></span> = <span class="idlConstValue">0x03</span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span>     <span class="idlAttrName"><a href="#widl-KeyboardEvent-key">key</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span>     <span class="idlAttrName"><a href="#widl-KeyboardEvent-code">code</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned long</span> <span class="idlAttrName"><a href="#widl-KeyboardEvent-location">location</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-ctrlKey">ctrlKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-shiftKey">shiftKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-altKey">altKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-metaKey">metaKey</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-repeat">repeat</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">boolean</span>       <span class="idlAttrName"><a href="#widl-KeyboardEvent-isComposing">isComposing</a></span>;</span>
<span class="idlMethod">    <span class="idlMethType">boolean</span> <span class="idlMethName"><a href="#widl-KeyboardEvent-getModifierState">getModifierState</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">keyArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-4" typeof="bibo:Chapter" id="attributes-4"><h5 resource="#h-attributes-4" id="h-attributes-4"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-KeyboardEvent-altKey"><code>altKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the <code title="Key Value" class="key">'Alt'</code> (alternative) (or <code title="Character Value Glyph" class="glyph">'Option'</code>) key modifier was active.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.</p>
          </dd><dt id="widl-KeyboardEvent-code"><code>code</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>code</code> holds a string that identifies the physical key being pressed.
               The value is not affected by the current keyboard layout or modifier state, so a particular
               key will always return the same value.
            </p>
            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).</p>
          </dd><dt id="widl-KeyboardEvent-ctrlKey"><code>ctrlKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the <code title="Key Value" class="key">'Control'</code> (control) key modifier was active.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.</p>
          </dd><dt id="widl-KeyboardEvent-isComposing"><code>isComposing</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the key event occurs as part of a composition session, i.e., after a
              <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a>
              event and before the corresponding
              <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a>
              event.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.
              </p>
          </dd><dt id="widl-KeyboardEvent-key"><code>key</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>key</code> holds the key value of the key pressed.
              If the value is has a printed representation, it <em title="MUST" class="rfc2119">MUST</em> be a non-empty Unicode character
              string, conforming to the <a href="#key-algorithm">algorithm for determining the key value</a> defined in this specification.
              If the value is a control key which has no printed representation, it <em title="MUST" class="rfc2119">MUST</em> be one of the key values defined in the
              <a href="#keys-keyvalues">key values set</a>, as determined by the <a href="#key-algorithm">algorithm for determining the key value</a>. Implementations that are
              unable to identify a key <em title="MUST" class="rfc2119">MUST</em> use the key value <code title="Key Value" class="key">'Unidentified'</code>.</p>

            <div class="note"><div id="h-note43" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <code>key</code> attribute is not related to the legacy <code>keyCode</code> attribute and does not have the same set of values.</p></div>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).</p>
          </dd><dt id="widl-KeyboardEvent-location"><code>location</code> of type <span class="idlAttrType">unsigned long</span>, readonly   </dt><dd>
            <p>The <code>location</code> attribute contains an indication of the location of the key on the device.</p>

            <p>This attribute <em title="MUST" class="rfc2119">MUST</em> be set to one of the DOM_KEY_LOCATION constants to indicate the location of a key on the device. In case a DOM implementation wishes to provide a new location value, a
              value different from the defined constant values <em title="MUST" class="rfc2119">MUST</em> be used.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.</p>
          </dd><dt id="widl-KeyboardEvent-metaKey"><code>metaKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the meta (<code title="Key Value" class="key">'Meta'</code>) key modifier was active.</p>

            <div class="note"><div id="h-note44" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <code title="Character Value Glyph" class="glyph">'Command'</code> (<code title="Character Value Glyph" class="glyph">'⌘'</code>) key modifier on Macintosh systems is represented using this key modifier.</p></div>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.</p>
          </dd><dt id="widl-KeyboardEvent-repeat"><code>repeat</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the key has been pressed in a sustained manner.  Holding down a key <em title="MUST" class="rfc2119">MUST</em> result in the repeating the events
              <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>,
              <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>,
              <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
              in this order, at a rate determined by the system configuration. For mobile devices which have <em>long-key-press</em>
              behavior, the first key event with a <a href="#widl-KeyboardEvent-repeat"><code>repeat</code></a> attribute value of <code>'true'</code> <em title="MUST" class="rfc2119">MUST</em> serve as an
              indication of a <em>long-key-press</em>. The length of time that the key <em title="MUST" class="rfc2119">MUST</em> be pressed in order to begin repeating is configuration-dependent.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.</p>
          </dd><dt id="widl-KeyboardEvent-shiftKey"><code>shiftKey</code> of type <span class="idlAttrType">boolean</span>, readonly   </dt><dd>
            <p><code>true</code> if the shift (<code title="Key Value" class="key">'Shift'</code>) key modifier was active.</p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>false</code>.</p>
          </dd></dl></section><section property="bibo:hasPart" resource="#methods-1" typeof="bibo:Chapter" id="methods-1"><h5 resource="#h-methods-1" id="h-methods-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.1.2 </span>Methods</span></h5><dl class="methods"><dt id="widl-KeyboardEvent-getModifierState"><code>getModifierState</code></dt><dd>
            <p>Queries the state of a modifier using a key value.
              See <a href="#keys-modifiers">Modifier keys</a> for a list of valid (case-sensitive) arguments to this method.
              </p>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">keyArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>A modifier key value.  Valid modifier keys are defined in the
                  <a href="http://www.w3.org/TR/DOM-Level-3-Events-key/#keys-modifier">Modifier Keys</a> table in
                  [<a href="#references-D3E-key">DOM3 key Values</a>].
                  </p>

                <p>Returns <code>true</code> if it is a modifier key and the modifier is activated, <code>false</code> otherwise.</p>

                <div class="note"><div id="h-note45" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> If an application wishes to distinguish between right and left modifiers, this information could be
                  deduced using keyboard events and <a href="#widl-KeyboardEvent-location"><code>KeyboardEvent.location</code></a>.</p></div>
              </td></tr></tbody></table><div><em>Return type: </em><code>boolean</code></div></dd></dl></section><section property="bibo:hasPart" resource="#constants-1" typeof="bibo:Chapter" id="constants-1"><h5 resource="#h-constants-1" id="h-constants-1"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.1.3 </span>Constants</span></h5><dl class="constants"><dt id="widl-KeyboardEvent-DOM_KEY_LOCATION_LEFT"><code>DOM_KEY_LOCATION_LEFT</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The key activated originated from the left key location (when there is more than one possible location for this key).</p>

            <div class="example">
              <div class="example-title"></div>
              <p>The left <code title="Key Value" class="key">'Control'</code> key on a PC 101 Key US keyboard.</p>
            </div>
          </dd><dt id="widl-KeyboardEvent-DOM_KEY_LOCATION_NUMPAD"><code>DOM_KEY_LOCATION_NUMPAD</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The key activation originated on the numeric keypad or with a virtual key corresponding to the numeric
              keypad (when there is more than one possible location for this key). Note that the <code title="Key Value" class="key">'NumLock'</code>
              key should always be encoded with a location of
              <a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_STANDARD"><code class="constant-name">DOM_KEY_LOCATION_STANDARD</code></a>.
              </p>

            <div class="example">
              <div class="example-title"></div>
              <p>The <code title="Key Value" class="key">'1'</code> key on a PC 101 Key US keyboard located on the numeric pad.</p>
            </div>
          </dd><dt id="widl-KeyboardEvent-DOM_KEY_LOCATION_RIGHT"><code>DOM_KEY_LOCATION_RIGHT</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The key activation originated from the right key location (when there is more than one possible location for this key).</p>

            <div class="example">
              <div class="example-title"></div>
              <p>The right <code title="Key Value" class="key">'Shift'</code> key on a PC 101 Key US keyboard.</p>
            </div>
          </dd><dt id="widl-KeyboardEvent-DOM_KEY_LOCATION_STANDARD"><code>DOM_KEY_LOCATION_STANDARD</code> of type <span class="idlConstType">unsigned long</span></dt><dd>
            <p>The key activation <em title="MUST NOT" class="rfc2119">MUST NOT</em> be distinguished as the left or right version of the key, and (other than the
              <code title="Key Value" class="key">'NumLock'</code> key) did not originate from the numeric keypad (or did not originate
              with a virtual key corresponding to the numeric keypad).</p>

            <div class="example">
              <div class="example-title"></div>
              <p>The <code title="Key Value" class="key">'Q'</code> key on a PC 101 Key US keyboard.</p>
              <p>The <code title="Key Value" class="key">'NumLock'</code> key on a PC 101 Key US keyboard.</p>
              <p>The <code title="Key Value" class="key">'1'</code> key on a PC 101 Key US keyboard located in the main section of the keyboard.</p>
            </div>
          </dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-KeyboardEventInit">dictionary <span class="idlDictionaryID">KeyboardEventInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-EventModifierInit"><code>EventModifierInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType">DOMString</span>     <span class="idlMemberName"><a href="#widl-KeyboardEventInit-key">key</a></span> = <span class="idlMemberValue">""</span>;</span>
<span class="idlMember">    <span class="idlMemberType">DOMString</span>     <span class="idlMemberName"><a href="#widl-KeyboardEventInit-code">code</a></span> = <span class="idlMemberValue">""</span>;</span>
<span class="idlMember">    <span class="idlMemberType">unsigned long</span> <span class="idlMemberName"><a href="#widl-KeyboardEventInit-location">location</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span>       <span class="idlMemberName"><a href="#widl-KeyboardEventInit-repeat">repeat</a></span> = <span class="idlMemberValue">false</span>;</span>
<span class="idlMember">    <span class="idlMemberType">boolean</span>       <span class="idlMemberName"><a href="#widl-KeyboardEventInit-isComposing">isComposing</a></span> = <span class="idlMemberValue">false</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-keyboardeventinit-members" typeof="bibo:Chapter" id="dictionary-keyboardeventinit-members"><h5 resource="#h-dictionary-keyboardeventinit-members" id="h-dictionary-keyboardeventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.1.4 </span>Dictionary <a href="#idl-def-KeyboardEventInit" class="idlType"><code>KeyboardEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-KeyboardEventInit-code"><code>code</code> of type <span class="idlMemberType">DOMString</span>, defaulting to <code>""</code></dt><dd>
            <p>Initializes the <code>code</code> attribute of the KeyboardEvent
              object to the unicode character string representing the key that
              was pressed, ignoring any keyboard modifications such as keyboard
              layout.
              This value should be one of the code values defined in
              [<a href="#references-D3E-code">DOM3 code Values</a>].
              </p>
          </dd><dt id="widl-KeyboardEventInit-isComposing"><code>isComposing</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>isComposing</code> attribute of the KeyboardEvent
              object. This attribute should be set to <code>true</code> if the
              event being constructed occurs as part of a composition sequence,
              <code>false</code> otherwise.
              </p>
          </dd><dt id="widl-KeyboardEventInit-key"><code>key</code> of type <span class="idlMemberType">DOMString</span>, defaulting to <code>""</code></dt><dd>
            <p>Initializes the <code>key</code> attribute of the KeyboardEvent
              object to the unicode character string representing the meaning of a
              key after taking into account all keyboard modifications (such as
              shift-state). This value is the final effective value of the key.
              If the key is not a printable character, then it should be one of
              the key values defined in
              [<a href="#references-D3E-key">DOM3 key Values</a>].
              </p>
          </dd><dt id="widl-KeyboardEventInit-location"><code>location</code> of type <span class="idlMemberType">unsigned long</span>, defaulting to <code>0</code></dt><dd>
            <p>Initializes the <code>location</code> attribute of the KeyboardEvent
              object to one of the following location numerical constants:
              </p>
            <ul>
              <li><code>KeyboardEvent.DOM_KEY_LOCATION_STANDARD</code> (numerical value 0)</li>
              <li><code>KeyboardEvent.DOM_KEY_LOCATION_LEFT</code> (numerical value 1)</li>
              <li><code>KeyboardEvent.DOM_KEY_LOCATION_RIGHT</code> (numerical value 2)</li>
              <li><code>KeyboardEvent.DOM_KEY_LOCATION_NUMPAD</code> (numerical value 3)</li>
            </ul>
          </dd><dt id="widl-KeyboardEventInit-repeat"><code>repeat</code> of type <span class="idlMemberType">boolean</span>, defaulting to <code>false</code></dt><dd>
            <p>Initializes the <code>repeat</code> attribute of the KeyboardEvent
              object. This attribute should be set to <code>true</code> if the the current KeyboardEvent is
              considered part of a repeating sequence of similar events caused
              by the long depression of any single key, <code>false</code> otherwise.
              </p>
          </dd></dl></section>

      </section>  <!-- interface-KeyboardEvent -->

      <div class="warning"><div class="warning-title"><span>Warning</span></div><div class="">
        <p><strong>Warning!</strong></p>
        <p>Legacy keyboard event implementations include three additional attributes,
          <code>keyCode</code>, <code>charCode</code>, and <code>which</code>.
          The <code>keyCode</code> attribute indicates a numeric value associated with
          a particular key on a computer keyboard,
          while the <code>charCode</code> attribute indicates the
          <abbr title="American Standard Code for Information Interchange">ASCII</abbr>
          value of the character associated with that key (which might be the same as
          the <code>keyCode</code> value) and is applicable only to keys that produce a
          <a class="def" href="#glossary-character-value">character value</a>.
          </p>
        <p>In practice, <code>keyCode</code> and <code>charCode</code> are inconsistent across platforms
          and even the same implementation on different operating systems or using different localizations.
          This specification does not define values for either
          <code>keyCode</code> or <code>charCode</code>, or behavior for <code>charCode</code>.
          In conforming UI Events implementations, content authors can instead use
          <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a> and
          <a href="#widl-KeyboardEvent-code"><code>KeyboardEvent.code</code></a>.
          </p>
        <p><em>For more information, see the informative appendix on
          <a href="#legacy-key-attributes">Legacy key attributes</a>.</em>
          </p>
        </div></div>

      <div class="note"><div id="h-note46" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        For compatibility with existing content, virtual keyboards, such as software keyboards
        on screen-based input devices, are expected to produce the normal range of keyboard
        events, even though they do not possess physical keys.
        </p></div>

      <div class="note"><div id="h-note47" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        In some implementations or system configurations, some key events, or their values,
        might be suppressed by the <a class="def" href="#glossary-ime">IME</a> in use.
        </p></div>

      <section property="bibo:hasPart" resource="#events-keyboard-event-order" typeof="bibo:Chapter" id="events-keyboard-event-order">
        <h4 resource="#h-events-keyboard-event-order" id="h-events-keyboard-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.5.2 </span>Keyboard Event Order</span></h4>
        <p>The keyboard events defined in this specification occur in a set order relative
          to one another, for any given key:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
            <td><em>(only for keys which produce a <a class="def" href="#glossary-character-value">character value</a>)</em></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em>Any <a class="def" href="#glossary-default-action">default actions</a> related to this key, such as inserting a
              character in to the DOM.</em></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
            <td><em>(only for keys which have updated the DOM)</em></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em>Any events as a result of the key being held for a sustained period (see below).</em></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
            <td></td>
          </tr>
        </tbody></table>

        <p>If the key is depressed for a sustained period, the following events <em title="MAY" class="rfc2119">MAY</em> repeat
          at an environment-dependent rate: <!-- and the key should seek counseling -->
          </p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td><em>(with <a href="#widl-KeyboardEvent-repeat">repeat</a> attribute set to <code> true</code>)</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
            <td><em>(only for keys which produce a <a class="def" href="#glossary-character-value">character value</a>)</em></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em>Any <a class="def" href="#glossary-default-action">default actions</a> related to this key, such as inserting a
              character in to the DOM.</em></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
            <td><em>(only for keys which have updated the DOM)</em></td>
          </tr>
        </tbody></table>

        <div class="note"><div id="h-note48" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          Typically, any <a class="def" href="#glossary-default-action">default actions</a>
          associated with any particular key are completed before the
          <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event is dispatched.
          This might delay the <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
          event slightly (though this is not likely to be a perceptible delay).
          </p></div>

        <p>The <a class="def" href="#glossary-event-target">event target</a> of a key event is
          the currently focused element which is processing the keyboard activity.
          This is often an HTML <code>input</code> element or a textual element which is editable,
          but <em title="MAY" class="rfc2119">MAY</em> be an element defined by the
          <a class="def" href="#glossary-host-language">host language</a> to accept keyboard input
          for non-text purposes, such as the activation of an accelerator key or trigger of some
          other behavior. If no suitable element is in focus, the event target will be the HTML
          <a href="#glossary-body-element">body element</a> if available,
          otherwise the <a href="#glossary-root-element">root element</a>.
          </p>

        <div class="note"><div id="h-note49" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          The <a class="def" href="#glossary-event-target">event target</a> might change between
          different key events.
          For example, a <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          event for the <code title="Key Value" class="key">'Tab'</code> key
          will likely have a different <a class="def" href="#glossary-event-target">event target</a>
          than the  <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
          event on the same keystroke.
          </p></div>
      </section>  <!-- events-keyboard-event-order -->

      <p>The keyboard event types are listed below.</p>

      <!-- keydown -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-keydown"><dfn id="dfn-keydown"><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>keydown</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Varies:
                  <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a> and <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a> events;
                  launch <a class="def" href="#glossary-text-composition-system">text composition system</a>;
                  <a class="eventtype" href="#event-type-blur"><code>blur</code></a> and <a class="eventtype" href="#event-type-focus"><code>focus</code></a> events;
                  <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event;
                  <a class="def" href="#glossary-activation-behavior">activation behavior</a>;
                  other event</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      focused element processing the key event or if no element focused, then the
                      <a href="#glossary-body-element">body element</a> if available, otherwise the
                      <a href="#glossary-root-element">root element</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-KeyboardEvent-key"><code class="attribute-name">KeyboardEvent.key</code></a>:
                      the key value of the key pressed.</li>
                    <li><a href="#widl-KeyboardEvent-code"><code class="attribute-name">KeyboardEvent.code</code></a>:
                      the code value associated with the key's physical placement on the keyboard.</li>
                    <li><a href="#widl-KeyboardEvent-location"><code class="attribute-name">KeyboardEvent.location</code></a>:
                      the location of the key on the device.</li>
                    <li><a href="#widl-KeyboardEvent-altKey"><code class="attribute-name">KeyboardEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-shiftKey"><code class="attribute-name">KeyboardEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-ctrlKey"><code class="attribute-name">KeyboardEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-metaKey"><code class="attribute-name">KeyboardEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-repeat"><code class="attribute-name">KeyboardEvent.repeat</code></a>:
                      <code>true</code> if a key has been depressed long enough to trigger key repetition, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-isComposing"><code class="attribute-name">KeyboardEvent.isComposing</code></a>:
                      <code>true</code> if the key event occurs as part of a composition session, otherwise <code>false</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a key is pressed down. The <a class="eventtype" href="#event-type-keydown">
              <code>keydown</code></a> event type is device dependent and relies on the capabilities of the input devices and how they are mapped in the operating system. This
              event type <em title="MUST" class="rfc2119">MUST</em> be generated after the <a class="def" href="#glossary-key-mapping">key mapping</a>.
              This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched before the
                <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>,
                <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>,
                and <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
              events associated with the same key.</p>

            <p>The default action of the <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event depends upon the key:</p>

            <ul>
              <li>If the key is associated with a character, the default action <em title="MUST" class="rfc2119">MUST</em> be to dispatch
                  a <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a> event
                  followed by an <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
                event.
                In the case where the key which is associated with multiple characters (such as with a macro or certain sequences of dead keys), the default action <em title="MUST" class="rfc2119">MUST</em>
                be to dispatch one set of
                  <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a> /
                  <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
                events for each character</li>

              <li>If the key is associated with a <a class="def" href="#glossary-text-composition-system">text composition system</a>, the default action <em title="MUST" class="rfc2119">MUST</em> be to launch that
                system</li>

              <li>If the key is the <code title="Key Value" class="key">'Tab'</code> key, the default action <em title="MUST" class="rfc2119">MUST</em> be to shift the document focus from the currently focused
                element (if any) to the new focused element, as described in <a href="#events-focusevent">Focus Event Types</a></li>

              <li>If the key is the <code title="Key Value" class="key">'Enter'</code> or <code title="Key Value" class="key">'&nbsp;'</code> key and the
                current focus is on a state-changing element, the default action <em title="MUST" class="rfc2119">MUST</em> be to dispatch a <a class="eventtype" href="#event-type-click"><code>click</code></a> event,
                and a <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> event if that event type is supported by the <a class="def" href="#glossary-user-agent">
                user agent</a> (refer to <a href="#event-flow-activation">activation triggers and behavior</a> for more details)</li>
            </ul>

            <p>If this event is canceled, the associated event types <em title="MUST NOT" class="rfc2119">MUST NOT</em> be dispatched, and the associated actions <em title="MUST NOT" class="rfc2119">MUST NOT</em> be performed.</p>

            <div class="note"><div id="h-note50" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> and <a class="eventtype" href="#event-type-keyup">
              <code>keyup</code></a> events are traditionally associated with detecting any key, not just those which produce a <a class="def" href="#glossary-character-value">character
              value</a>.</p></div>
          </dd>
        </dl>
      </div>

      <!-- keyup -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-keyup"><dfn id="dfn-keyup"><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>keyup</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      focused element processing the key event or if no element focused, then the
                      <a href="#glossary-body-element">body element</a> if available, otherwise the
                      <a href="#glossary-root-element">root element</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-KeyboardEvent-key"><code class="attribute-name">KeyboardEvent.key</code></a>:
                      the key value of the key pressed.</li>
                    <li><a href="#widl-KeyboardEvent-code"><code class="attribute-name">KeyboardEvent.code</code></a>:
                      the code value associated with the key's physical placement on the keyboard.</li>
                    <li><a href="#widl-KeyboardEvent-location"><code class="attribute-name">KeyboardEvent.location</code></a>:
                      the location of the key on the device.</li>
                    <li><a href="#widl-KeyboardEvent-altKey"><code class="attribute-name">KeyboardEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-shiftKey"><code class="attribute-name">KeyboardEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-ctrlKey"><code class="attribute-name">KeyboardEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-metaKey"><code class="attribute-name">KeyboardEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-repeat"><code class="attribute-name">KeyboardEvent.repeat</code></a>:
                      <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-isComposing"><code class="attribute-name">KeyboardEvent.isComposing</code></a>:
                      <code>true</code> if the key event occurs as part of a composition session, otherwise <code>false</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a key is released.
              The <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event type is device dependent and relies on the
              capabilities of the input devices and how they are mapped in the operating system.
              This event type <em title="MUST" class="rfc2119">MUST</em> be generated after the <a class="def" href="#glossary-key-mapping">key mapping</a>.
              This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the
                <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>,
                <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>,
                and <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
              events associated with the same key.</p>

            <div class="note"><div id="h-note51" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> the <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> and <a class="eventtype" href="#event-type-keyup">
              <code>keyup</code></a> events are traditionally associated with detecting any key, not just those which produce a <a class="def" href="#glossary-character-value">character
              value</a>.</p></div>
          </dd>
        </dl>
      </div>
    </section>  <!-- events-keyboardevents -->

    <section property="bibo:hasPart" resource="#events-compositionevents" typeof="bibo:Chapter" id="events-compositionevents">
      <h3 resource="#h-events-compositionevents" id="h-events-compositionevents"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6 </span>Composition Event Types</span></h3>

      <p>Composition Events provide a means for inputing text in a supplementary or alternate
        manner than by Keyboard Events, in order to allow the use of characters that
        might not be commonly available on keyboard.
        For example, Composition Events might be used
          to add accents to characters despite their absence from standard US keyboards,
          to build up logograms of many Asian languages from their base components or categories,
          to select word choices from a combination of key presses on a mobile device keyboard,
          or to convert voice commands into text using a speech recognition processor.
        Refer to <a href="#keys">Keyboard events and key values</a> for examples
        on how Composition Events are used in combination with keyboard events.
        </p>

      <p>Conceptually, a composition session consists of one
          <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a>
        event, one or more
          <a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a>
        events, and one
          <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a>
        event, with the value of the <a href="#widl-CompositionEvent-data"><code>data</code></a>
        attribute persisting between each <q>stage</q> of this event chain during each session.
        </p>

      <div class="note"><div id="h-note52" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        While a composition session is active, keyboard events can be dispatched to the DOM
        if the keyboard is the input device used with the composition session.
        See the <a href="#event-type-compositionstart"><code>compositionstart</code> event details</a>
        and <a href="#keys-IME">IME section</a> for relevent event ordering.
        </p></div>

      <p>Not all <a class="def" href="#glossary-ime">IME</a> systems or devices expose the necessary
        data to the DOM, so the active composition string (the <q>Reading Window</q>
        or <q>candidate selection menu option</q>) might not be available through this interface,
        in which case the selection <em title="MAY" class="rfc2119">MAY</em> be represented by the
        <a class="def" href="#glossary-empty-string">empty string</a>.
        </p>

      <section property="bibo:hasPart" resource="#interface-CompositionEvent" typeof="bibo:Chapter" id="interface-CompositionEvent">
        <h4 resource="#h-interface-compositionevent" id="h-interface-compositionevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.1 </span>Interface CompositionEvent</span></h4>

        <p class="intro-dom">Introduced in this specification</p>

        <p>The <code>CompositionEvent</code> interface provides specific contextual information associated with Composition Events.</p>

        <p>To create an instance of the <code>CompositionEvent</code> interface, use the <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("CompositionEvent")</code></a>
          method call.</p>

        <pre class="idl"><span class="idlInterface" id="idl-def-CompositionEvent">[<span class="extAttr">Constructor(DOMString typeArg, optional CompositionEventInit compositionEventInitDict)</span>]
interface <span class="idlInterfaceID">CompositionEvent</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEvent"><code>UIEvent</code></a></span> {
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span> <span class="idlAttrName"><a href="#widl-CompositionEvent-data">data</a></span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-5" typeof="bibo:Chapter" id="attributes-5"><h5 resource="#h-attributes-5" id="h-attributes-5"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-CompositionEvent-data"><code>data</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>data</code> holds the value of the characters generated by an input method.
              This <em title="MAY" class="rfc2119">MAY</em> be a single Unicode character or a non-empty sequence of Unicode characters
              [<cite><a class="normative" href="#references-Unicode">Unicode</a></cite>].
              Characters <em title="SHOULD" class="rfc2119">SHOULD</em> be normalized as defined by the Unicode normalization form <em>NFC</em>,
              defined in [<cite><a class="normative" href="#references-UnicodeNormalization">UAX #15</a></cite>].
              This attribute <em title="MAY" class="rfc2119">MAY</em> be the <a class="def" href="#glossary-empty-string">empty string</a>.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this attribute
              <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).
              </p>
          </dd></dl></section>

        <pre class="idl"><span class="idlDictionary" id="idl-def-CompositionEventInit">dictionary <span class="idlDictionaryID">CompositionEventInit</span> : <span class="idlSuperclass"><a class="idlType" href="#idl-def-UIEventInit"><code>UIEventInit</code></a></span> {
<span class="idlMember">    <span class="idlMemberType">DOMString</span> <span class="idlMemberName"><a href="#widl-CompositionEventInit-data">data</a></span> = <span class="idlMemberValue">""</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-compositioneventinit-members" typeof="bibo:Chapter" id="dictionary-compositioneventinit-members"><h5 resource="#h-dictionary-compositioneventinit-members" id="h-dictionary-compositioneventinit-members"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.1.2 </span>Dictionary <a href="#idl-def-CompositionEventInit" class="idlType"><code>CompositionEventInit</code></a> Members</span></h5><dl class="dictionary-members"><dt id="widl-CompositionEventInit-data"><code>data</code> of type <span class="idlMemberType">DOMString</span>, defaulting to <code>""</code></dt><dd>
            <p>Initializes the <code>data</code> attribute of the CompositionEvent
              object to the characters generated by the IME composition.
              </p>
          </dd></dl></section>

      </section>  <!-- interface-CompositionEvent -->

      <section property="bibo:hasPart" resource="#events-composition-event-order" typeof="bibo:Chapter" id="events-composition-event-order">
        <h4 resource="#h-events-composition-event-order" id="h-events-composition-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.2 </span>Composition Event Order</span></h4>

        <p>The Composition Events defined in this specification <em title="MUST" class="rfc2119">MUST</em> occur in the following set order relative to one another:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
            <td>Multiple events</td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
            <td></td>
          </tr>
        </tbody></table>
      </section>  <!-- events-composition-event-order -->

      <section property="bibo:hasPart" resource="#handwriting" typeof="bibo:Chapter" id="handwriting">
        <h4 resource="#h-handwriting" id="h-handwriting"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.3 </span>Handwriting Recognition Systems</span></h4>
        <p>The following example describes a possible sequence of events when composing a text passage <q>text</q> with a handwriting recognition system, such as on a pen
          tablet, as modeled using Composition Events.</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th><a href="#widl-CompositionEvent-data"><code>CompositionEvent<br>data</code></a></th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
            <td><code>''</code></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>User writes word on tablet surface</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
            <td><code>'test'</code></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td></td>
            <td><em>User rejects first word-match suggestion, selects different match</em></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
            <td><code>'text'</code></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
            <td><code>'text'</code></td>
            <td></td>
          </tr>
        </tbody></table>
      </section>  <!-- handwriting -->

      <section property="bibo:hasPart" resource="#events-composition-event-canceling" typeof="bibo:Chapter" id="events-composition-event-canceling">
        <h4 resource="#h-events-composition-event-canceling" id="h-events-composition-event-canceling"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.4 </span>Canceling Composition Events</span></h4>
        <p>If a <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event is canceled then any
        Composition Events that would have fired as a result of that
        <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> <em title="SHOULD" class="rfc2119">SHOULD</em> not be dispatched:</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td>The <a class="def" href="#glossary-default-action">default action</a> is
              prevented, e.g., by invoking <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>.
              </td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em><abbr title="Number, Other">No</abbr> Composition Events are dispatched</em></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
            <td></td>
          </tr>
        </tbody></table>

        <p>If the initial <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a> event is
          canceled then the text composition session <em title="SHOULD" class="rfc2119">SHOULD</em> be terminated. Regardless of whether or not the composition
          session is terminated, the <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a>
          event <em title="MUST" class="rfc2119">MUST</em> be sent.</p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <th>Event Name</th>
            <th>Notes</th>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
            <td>The <a class="def" href="#glossary-default-action">default action</a> is
              prevented, e.g., by invoking <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>.
              </td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td></td>
            <td><em><abbr title="Number, Other">No</abbr> Composition Events are dispatched</em></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
            <td></td>
          </tr>
        </tbody></table>
      </section>  <!-- events-composition-event-canceling -->

      <section property="bibo:hasPart" resource="#events-composition-event-key-events" typeof="bibo:Chapter" id="events-composition-event-key-events">
        <h4 resource="#h-events-composition-event-key-events" id="h-events-composition-event-key-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.5 </span>Key Events During Composition</span></h4>
        <p>During the composition session, all <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          and <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events <em title="MAY" class="rfc2119">MAY</em> be suppressed.</p>

        <section property="bibo:hasPart" resource="#events-composition-event-including-key-events" typeof="bibo:Chapter" id="events-composition-event-including-key-events">
          <h5 resource="#h-events-composition-event-including-key-events" id="h-events-composition-event-including-key-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.5.1 </span>Including Key Events During Composition</span></h5>

          <p>If a <a class="def" href="#glossary-user-agent">user agent</a> does not suppress these events during
            composition, then it <em title="MUST" class="rfc2119">MUST</em> set the key event's
              <a href="#widl-KeyboardEvent-isComposing"><code>isComposing</code></a>
            attribute to <code>true</code> for any events that occur during a composition session.
            </p>

          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code>false</code></td>
              <td>This is the key event that initiates the composition.</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code>true</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td>...</td>
              <td></td>
              <td>Any key events sent during the composition session <em title="MUST" class="rfc2119">MUST</em> have <code>isComposing</code> set to <code>true</code>.</td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code>true</code></td>
              <td>This is the key event that exits the composition.</td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">7.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code>false</code></td>
              <td></td>
            </tr>
          </tbody></table>

        </section> <!-- events-composition-event-including-key-events -->

        <section property="bibo:hasPart" resource="#events-composition-event-suppressing-key-events" typeof="bibo:Chapter" id="events-composition-event-suppressing-key-events">
          <h5 resource="#h-events-composition-event-suppressing-key-events" id="h-events-composition-event-suppressing-key-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.5.2 </span>Suppressing Key Events During Composition</span></h5>

          <p>If key events are suppressed between
            <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a> and
            <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a>, then the first
            or last key pressed might result in unmatched
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> and
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events.
            If a <a class="def" href="#glossary-user-agent">user agent</a> suppresses key events during composition,
            then it <em title="MUST" class="rfc2119">MUST</em> ensure that all <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> and
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events occur in matching pairs.
            </p>

          <p>To ensure that the initial <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> has a
            matching <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>, a
            <a class="def" href="#glossary-user-agent">user agent</a> might insert an extra
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> to match the
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> that initiated a composition session,
            as shown in the following example:
            </p>

          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code>false</code></td>
              <td>This is the key event that initiates the composition.</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code>true</code></td>
              <td>This event would normally be suppressed because of the ongoing composition session, but it is sent
                to match the previously sent <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
                event.</td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td>...</td>
              <td></td>
              <td>Any other key events that occur during the composition session are suppressed.</td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td></td>
              <td></td>
            </tr>
          </tbody></table>

          <p>To ensure that the composition session doesn't end with a dangling
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event, a
            <a class="def" href="#glossary-user-agent">user agent</a> can choose either (A) to suppress this
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event, or (B) to insert an extra
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event.</p>

          <p>An example event sequence where both the
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> and
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events have
            been suppressed:</p>

          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td></td>
              <td></td>
              <td><em><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> for key that exits IME suppressed
                during composition session</em></td>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td></td>
              <td></td>
              <td><em>A <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event would normally be sent
                at this time, but it is suppressed to avoid generating an unmatched
                <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event.</em></td>
            </tr>
          </tbody></table>

          <p>An example event sequence where a <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> has been inserted:
            </p>

          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td></td>
              <td></td>
              <td><em><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> for key that exits IME suppressed
                during composition session</em></td>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code>false</code></td>
              <td>This is key event that was suppressed earlier. It is sent now to match the upcoming
                <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>.</td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code>false</code></td>
              <td></td>
            </tr>
          </tbody></table>

        </section> <!-- events-composition-event-suppressing-key-events -->

      </section>  <!-- events-composition-event-key-events -->

      <section property="bibo:hasPart" resource="#events-composition-event-types" typeof="bibo:Chapter" id="events-composition-event-types">
        <h4 resource="#h-events-composition-event-types" id="h-events-composition-event-types"><span property="xhv:role" resource="xhv:heading"><span class="secno">5.6.6 </span>Composition Event Types</span></h4>
        <p>The composition event types are listed below.</p>

        <!-- compositionstart -->
        <div class="event-definition">
          <dl>
            <dt id="event-type-compositionstart"><dfn id="dfn-compositionstart"><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></dfn></dt>
            <dd>
              <table class='old_css_table'>
                <tbody><tr>
                  <th>Type</th>
                  <td><strong><code>compositionstart</code></strong></td>
                </tr>
                <tr>
                  <th>Interface</th>
                  <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
                </tr>
                <tr>
                  <th>Sync / Async</th>
                  <td>Sync</td>
                </tr>
                <tr>
                  <th>Bubbles</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Trusted Targets</th>
                  <td><code>Element</code></td>
                </tr>
                <tr>
                  <th>Cancelable</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Default action</th>
                  <td>Start a new composition session when a <a class="def" href="#glossary-text-composition-system">text composition system</a> is enabled</td>
                </tr>
                <tr>
                  <th>Context<br>(trusted events)</th>
                  <td>
                    <ul>
                      <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                        focused element processing the composition</li>
                      <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                        <a class="def" href="#glossary-window"><code>Window</code></a></li>
                      <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                        <code>0</code></li>
                      <li><a href="#widl-CompositionEvent-data"><code class="attribute-name">CompositionEvent.data</code></a>:
                        the original string being edited, otherwise the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    </ul>
                  </td>
                </tr>
              </tbody></table>

              <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a <a class="def" href="#glossary-text-composition-system">text composition
                system</a> is enabled and a new composition session is about to begin (or has begun, depending on the <a class="def" href="#glossary-text-composition-system">text composition
                system</a>) in preparation for composing a passage of text. This event type is device-dependent, and <em title="MAY" class="rfc2119">MAY</em> rely upon the capabilities of the text conversion system and how it is
                mapped into the operating system. When a keyboard is used to feed an input method editor, this event type is generated after a <a href="#dfn-keydown" class="eventtype internalDFN"><code>keydown</code></a> event,
                but speech or handwriting recognition systems <em title="MAY" class="rfc2119">MAY</em> send this event type without keyboard events.  Some implementations <em title="MAY" class="rfc2119">MAY</em> populate the
                <a href="#widl-CompositionEvent-data"><code>data</code></a> attribute of the <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a> event
                with the text currently selected in the document (for editing and replacement). Otherwise, the value of the <a href="#widl-CompositionEvent-data"><code>data</code></a>
                attribute <em title="MUST" class="rfc2119">MUST</em> be  the <a class="def" href="#glossary-empty-string">empty string</a>.</p>

              <p>This event <em title="MUST" class="rfc2119">MUST</em> be dispatched immediately before a <a class="def" href="#glossary-text-composition-system">text composition system</a> begins a new composition session, and
                before the DOM is modified due to the composition process. The default action of this event is for the <a class="def" href="#glossary-text-composition-system">text
                composition system</a> to start a new composition session. If this event is canceled, the <a class="def" href="#glossary-text-composition-system">text composition system</a> <em title="SHOULD" class="rfc2119">SHOULD</em>
                discard the current composition session.</p>

              <div class="note"><div id="h-note53" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Canceling the <a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a> <em>event type</em> is distinct
                from canceling the <a class="def" href="#glossary-text-composition-system">text composition system</a> itself (e.g., by hitting a cancel button or closing an <a class="def" href="#glossary-ime">IME</a> window).</p></div>

              <div class="note"><div id="h-note54" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Some IMEs do not support cancelling an in-progress composition session (e.g., such as GTK which doesn't presently have such an API). In these
                cases, calling <a href="#widl-Event-preventDefault"><code>preventDefault</code></a> will not stop this event's default action.</p></div>
            </dd>
          </dl>
        </div>

        <!-- compositionupdate -->
        <div class="event-definition">
          <dl>
            <dt id="event-type-compositionupdate"><dfn id="dfn-compositionupdate"><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></dfn></dt>
            <dd>
              <table class='old_css_table'>
                <tbody><tr>
                  <th>Type</th>
                  <td><strong><code>compositionupdate</code></strong></td>
                </tr>
                <tr>
                  <th>Interface</th>
                  <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
                </tr>
                <tr>
                  <th>Sync / Async</th>
                  <td>Sync</td>
                </tr>
                <tr>
                  <th>Bubbles</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Trusted Targets</th>
                  <td><code>Element</code></td>
                </tr>
                <tr>
                  <th>Cancelable</th>
                  <td><abbr title="Number, Other">No</abbr></td>
                </tr>
                <tr>
                  <th>Default action</th>
                  <td>None</td>
                </tr>
                <tr>
                  <th>Context<br>(trusted events)</th>
                  <td>
                    <ul>
                      <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                        focused element processing the composition, <code>null</code> if not accessible</li>
                      <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                        <a class="def" href="#glossary-window"><code>Window</code></a></li>
                      <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                        <code>0</code></li>
                      <li><a href="#widl-CompositionEvent-data"><code class="attribute-name">CompositionEvent.data</code></a>:
                        the string comprising the current results of the composition session, which <em title="MAY" class="rfc2119">MAY</em> be the
                        <a class="def" href="#glossary-empty-string">empty string</a> if the content has been deleted</li>
                    </ul>
                  </td>
                </tr>
              </tbody></table>
              <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="SHOULD" class="rfc2119">SHOULD</em> dispatch this event during a composition session when a
                <a class="def" href="#glossary-text-composition-system">text composition system</a> updates its active text passage with a
                new character, which is reflected in the string in <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a>.
                </p>

              <p>In <a class="def" href="#glossary-text-composition-system">text composition systems</a> which keep the ongoing composition in sync
                with the input control, the <a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a> event
                <em title="MUST" class="rfc2119">MUST</em> be dispatched before the control is updated.
                </p>

              <p>Some <a class="def" href="#glossary-text-composition-system">text composition systems</a> might not expose this information to the DOM,
                in which case this event will not fire during the composition process.
                </p>

              <p>If the composition session is canceled, this event will be fired immediately before the
                <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a> event,
                and the <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a> attribute will be set to the
                <a class="def" href="#glossary-empty-string">empty string</a>.
                </p>
            </dd>
          </dl>
        </div>

        <!-- compositionend -->
        <div class="event-definition">
          <dl>
            <dt id="event-type-compositionend"><dfn id="dfn-compositionend"><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></dfn></dt>
            <dd>
              <table class='old_css_table'>
                <tbody><tr>
                  <th>Type</th>
                  <td><strong><code>compositionend</code></strong></td>
                </tr>
                <tr>
                  <th>Interface</th>
                  <td><a href="#interface-CompositionEvent"><code>CompositionEvent</code></a></td>
                </tr>
                <tr>
                  <th>Sync / Async</th>
                  <td>Sync</td>
                </tr>
                <tr>
                  <th>Bubbles</th>
                  <td>Yes</td>
                </tr>
                <tr>
                  <th>Trusted Targets</th>
                  <td><code>Element</code></td>
                </tr>
                <tr>
                  <th>Cancelable</th>
                  <td><abbr title="Number, Other">No</abbr></td>
                </tr>
                <tr>
                  <th>Default action</th>
                  <td>None</td>
                </tr>
                <tr>
                  <th>Context<br>(trusted events)</th>
                  <td>
                    <ul>
                      <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                        focused element processing the composition</li>
                      <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                        <a class="def" href="#glossary-window"><code>Window</code></a></li>
                      <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                        <code>0</code></li>
                      <li><a href="#widl-CompositionEvent-data"><code class="attribute-name">CompositionEvent.data</code></a>:
                        the string comprising the final result of the composition session, which <em title="MAY" class="rfc2119">MAY</em> be the
                        <a class="def" href="#glossary-empty-string">empty string</a> if the content has been deleted or if the composition process has been canceled</li>
                    </ul>
                  </td>
                </tr>
              </tbody></table>
              <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a
                <a class="def" href="#glossary-text-composition-system">text composition system</a> completes or cancels the current composition session,
                and the <a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a> event <em title="MUST" class="rfc2119">MUST</em> be dispatched after the control is updated.
                </p>

              <p>This event is dispatched immediately after the <a class="def" href="#glossary-text-composition-system">text composition system</a> completes
                the composition session (e.g., the <a class="def" href="#glossary-ime">IME</a> is closed, minimized, switched out of focus, or otherwise dismissed,
                and the focus switched back to the <a class="def" href="#glossary-user-agent">user agent</a>).
                </p>
            </dd>
          </dl>
        </div>
      </section>  <!-- events-composition-event-types -->
    </section>  <!-- events-compositionevents -->

  </section>  <!-- event-types -->

  <!-- Section 6: Keyboard and key values ========================================================-->
  <section property="bibo:hasPart" resource="#keys" typeof="bibo:Chapter" id="keys">
    <!--OddPage--><h2 resource="#h-keys" id="h-keys"><span property="xhv:role" resource="xhv:heading"><span class="secno">6. </span>Keyboard events and key values</span></h2>

    <p>This section contains necessary information regarding keyboard events:</p>

    <ul>
      <li>Explanation of keyboard layout, mapping, and key values.</li>
      <li>Relations between keys, such as <a class="def" href="#glossary-dead-key">dead keys</a> or modifiers keys.</li>
      <li>Relations between keyboard events and their default actions.</li>
      <li>The set of <code>key</code> values, and guidelines on how to extend this set.</li>
    </ul>

    <div class="note"><div id="h-note55" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> This section uses Serbian and Kanji characters which could
      be misrepresented or unavailable in the PDF version or printed version of this specification.
      </p></div>

    <section property="bibo:hasPart" resource="#keyboard-input" typeof="bibo:Chapter" id="keyboard-input">
      <h3 resource="#h-keyboard-input" id="h-keyboard-input"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.1 </span>Keyboard Input</span></h3>

      <p><em>This section is informative</em></p>

      <p>The relationship of each key to the complete keyboard has three separate aspects,
        each of which vary among different models and configurations of keyboards, particularly
        for locale-specific reasons:
        </p>

      <ul>
        <li><strong>Mechanical layout:</strong> the dimensions, size, and placement of the physical keys on the keyboard</li>
        <li><strong>Visual markings:</strong> the labels (or <em>legends</em>) that mark each key</li>
        <li><strong>Functional mapping:</strong> the abstract key-value association of each key.</li>
      </ul>

      <p>This specification only defines the functional mapping, in terms of
          <a href="#keys-keyvalues"><code>key</code></a> values and
          <a href="#keys-codevalues"><code>code</code></a> values,
        but briefly describes
          <a href="#key-legends">key legends</a>
        for background.
        </p>

      <section property="bibo:hasPart" resource="#key-legends" typeof="bibo:Chapter" id="key-legends">
        <h4 resource="#h-key-legends" id="h-key-legends"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.1.1 </span>Key Legends</span></h4>

        <p><em>This section is informative</em></p>

        <p>The key legend is the visual marking that is printed or embossed on the <em>key cap</em> (the rectangular
          'cap' that covers the mechanical switch for the key).
          These markings normally consist of one or more characters that a keystroke on that key
          will produce (such as
            <code title="Character Value Glyph" class="glyph">'F'</code>,
            <code title="Character Value Glyph" class="glyph">'8'</code>, or
            <code title="Character Value Glyph" class="glyph">'ш'</code>),
          or names or symbols which indicate that key's function (such as an upward-pointing arrow
          <code title="Character Value Glyph" class="glyph">⇧</code> indicating <code title="Key Value" class="key">'Shift'</code>,
          or the string <code>'Enter'</code>).
          Keys are often referred to by this marking
          (e.g., <q>Press the <code>'Shift'</code> and <code>'F'</code> keys.</q>).
          Note, however, that the visual appearance of the key has no bearing on its digital representation,
          and in many configurations may be completely inaccurate.
          Even the control and function keys, such as <code>'Enter'</code>, <em title="MAY" class="rfc2119">MAY</em> be mapped to different
          functionality, or even mapped as character keys.
          </p>

        <p>For historical reasons, the character keys are typically marked with the capital-letter equivalents
          of the character value they produce, e.g., the <code>'F'</code> key (the key marked with the glyph
          <code title="Character Value Glyph" class="glyph">'F'</code>), will produce the character value <code title="Character Value" class="char">'f'</code> when
          pressed without an active modifier key (<code title="Key Value" class="key">'Shift'</code>) or modifier state
          (<code title="Key Value" class="key">'CapsLock'</code>).
          </p>

        <div class="note"><div id="h-note56" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          Many keyboards contain keys that do not normally produce any characters, even though the symbol might
          have a Unicode equivalent.
          For example, the <code title="Key Value" class="key">'Shift'</code> key might bear the symbol
          <code title="Character Value Glyph" class="glyph">⇧</code>, which has the
          <a class="def" href="#glossary-unicode-code-point">Unicode code point</a> <code title="Character Value" class="char">'\u21E7'</code>,
          but pressing the <code title="Key Value" class="key">'Shift'</code> key will not produce this character value, and
          there is no <a class="def" href="#glossary-unicode-code-point">Unicode code point</a> for
          <code title="Key Value" class="key">'Shift'</code>.
          </p></div>
      </section>  <!-- key-legends -->

    </section>  <!-- keyboard-input -->

    <section property="bibo:hasPart" resource="#keys-codevalues" typeof="bibo:Chapter" id="keys-codevalues">
      <h3 resource="#h-keys-codevalues" id="h-keys-codevalues"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2 </span>Key codes</span></h3>

      <p>A key <code>code</code> is an attribute of a keyboard event that can be used to identify the physical
        key associated with the keyboard event. It is similar to USB Usage IDs in that it provides
        a low-level value (similar to a scancode) that is vendor-neutral.
        </p>

      <p>The primary purpose of the <code>code</code> attribute is to provide a consistent and coherent way
        to identify keys based on their physical location. In addition, it also provides a stable name
        (unaffected by the current keyboard state) that uniquely identifies each key on the keyboard.
        </p>

      <p>The list of valid <code>code</code> values is defined in the
        DOM Level 3 KeyboardEvent code Values Specification [<a href="#references-D3E-code">DOM3 code Values</a>].
        </p>

      <section property="bibo:hasPart" resource="#code-motivation" typeof="bibo:Chapter" id="code-motivation">
        <h4 resource="#h-code-motivation" id="h-code-motivation"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2.1 </span>Motivation for Adding the <code>code</code> Attribute</span></h4>

        <p>The standard PC keyboard has a set of keys (which
          we refer to as <em>writing system keys</em>)
          that generate different <code>key</code> values
          based on the current keyboard layout selected by the user.
          This situation makes it difficult to write code that detects keys based on their physical
          location since the code would need to know which layout is in effect in order to know which
          <code>key</code> values to check for.
          A real-world example of this is a game that wants to use the
            <code title="Character Value Glyph" class="glyph">'W'</code>,
            <code title="Character Value Glyph" class="glyph">'A'</code>,
            <code title="Character Value Glyph" class="glyph">'S'</code> and
            <code title="Character Value Glyph" class="glyph">'D'</code>
          keys to control player movement.
          The <code>code</code> attribute solves this problem by providing
          a stable value to check that is <em>not affected by the current keyboard layout</em>.
          </p>

        <p>In addition, the values in the <code>key</code> attribute depend as well
          on the current keyboard state.
          Because of this, the order in which keys are pressed and released in relation to modifier keys
          can affect the values stored in the <code>key</code> attribute.
          The <code>code</code> attribute solves this problem by providing
          a stable value that is <em>not affected by the current keyboard state</em>.
          </p>
      </section>  <!-- code-motivation -->

      <section property="bibo:hasPart" resource="#relationship-between-key-code" typeof="bibo:Chapter" id="relationship-between-key-code">
        <h4 resource="#h-relationship-between-key-code" id="h-relationship-between-key-code"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2.2 </span>The Relationship Between <code>key</code> and <code>code</code></span></h4>
        <dl>
          <dt><code>key</code></dt>
          <dd>The <code>key</code> attribute is intended for users who are interested in the meaning of the key
            being pressed, taking into account the current keyboard layout (and IME; <a href="#keys-dead">dead keys</a>
            are given a unique <code>key</code> value).
            Example use case: Detecting modified keys or bare modifier keys (e.g., to perform an action in
            response to a keyboard shortcut).</dd>

          <dt><code>code</code></dt>
          <dd>The <code>code</code> attribute is intended for users who are interested in the key that was pressed
            by the user, without any layout modifications applied.
            Example use case: Detecting WASD keys (e.g., for movement controls in a game) or trapping all keys
            (e.g., in a remote desktop client to send all keys to the remote host).
            </dd>
        </dl>
      </section>  <!-- relationship-between-key-code -->

      <section property="bibo:hasPart" resource="#code-examples" typeof="bibo:Chapter" id="code-examples">
        <h4 resource="#h-code-examples" id="h-code-examples"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2.3 </span><code>code</code> Examples</span></h4>
        <div class="example">
          <div class="example-title"></div>
          <p>Handling the Left and Right Alt Keys</p>
          <table class="data-table" style="width:auto">
            <thead>
              <tr>
                <th>Keyboard Layout</th>
                <th><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
                <th><a href="#widl-KeyboardEvent-code"><code>KeyboardEvent<br>code</code></a></th>
                <th>Notes</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td>US</td>
                <td><code title="Key Value" class="key">'Alt'</code></td>
                <td><code title="Code Value" class="code">'AltLeft'</code></td>
                <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
              </tr>
              <tr>
                <td>French</td>
                <td><code title="Key Value" class="key">'Alt'</code></td>
                <td><code title="Code Value" class="code">'AltLeft'</code></td>
                <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
              </tr>
              <tr>
                <td>US</td>
                <td><code title="Key Value" class="key">'Alt'</code></td>
                <td><code title="Code Value" class="code">'AltRight'</code></td>
                <td><code class="constant-name">DOM_KEY_LOCATION_RIGHT</code></td>
              </tr>
              <tr>
                <td>French</td>
                <td><code title="Key Value" class="key">'AltGr'</code></td>
                <td><code title="Code Value" class="code">'AltRight'</code></td>
                <td><code class="constant-name">DOM_KEY_LOCATION_RIGHT</code></td>
              </tr>
            </tbody>
          </table>
          <p>In this example, checking the <code>key</code> attribute permits matching <code title="Key Value" class="key">'Alt'</code> without worrying about which Alt key (left or right) was pressed.
            Checking the <code>code</code> attribute permits matching the right Alt key (<code title="Code Value" class="code">'AltRight'</code>) without worrying about which layout is currently in effect.
            </p>
          <p>Note that, in the French example, the <code title="Key Value" class="key">'Alt'</code> and
            <code title="Key Value" class="key">'AltGr'</code> keys retain their left and right location, even through there
            is only one of each key.
            </p>
        </div>  <!-- Handling Left and Right Alt Keys -->

        <div class="example">
          <div class="example-title"></div>
          <p>Handling the Single Quote Key</p>
          <table class="data-table" style="width:auto">
            <thead>
              <tr>
                <th>Keyboard Layout</th>
                <th><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
                <th><a href="#widl-KeyboardEvent-code"><code>KeyboardEvent<br>code</code></a></th>
                <th>Notes</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td>US</td>
                <td><code title="Key Value" class="key">'''</code></td>
                <td><code title="Code Value" class="code">'Quote'</code></td>
                <td></td>
              </tr>
              <tr>
                <td>Japanese</td>
                <td><code title="Key Value" class="key">':'</code></td>
                <td><code title="Code Value" class="code">'Quote'</code></td>
                <td></td>
              </tr>
              <tr>
                <td>US Intl</td>
                <td><code title="Key Value" class="key">'Dead'</code></td>
                <td><code title="Code Value" class="code">'Quote'</code></td>
                <td></td>
              </tr>
            </tbody>
          </table>
          <p>This example shows how dead key values are encoded in the attributes. The
            <code>key</code> values vary based on the current locale, whereas the <code>code</code> attribute
            returns a consistent value.
            </p>
        </div><!-- Handling the Single Quote Key -->

        <div class="example" id="example-key-2">
          <div class="example-title"></div>
          <p>Handling the <code title="Character Value Glyph" class="glyph">'2'</code> Key (with and without Shift pressed)</p>
          <table class="data-table" style="width:auto">
            <thead>
              <tr>
                <th>Keyboard Layout</th>
                <th><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
                <th><a href="#widl-KeyboardEvent-code"><code>KeyboardEvent<br>code</code></a></th>
                <th>Notes</th>
              </tr>
            </thead>
            <tbody>
              <tr>
                <td>US</td>
                <td><code title="Key Value" class="key">'2'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td></td>
              </tr>
              <tr>
                <td>US</td>
                <td><code title="Key Value" class="key">'@'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              </tr>
              <tr>
                <td>UK</td>
                <td><code title="Key Value" class="key">'2'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td></td>
              </tr>
              <tr>
                <td>UK</td>
                <td><code title="Key Value" class="key">'"'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              </tr>
              <tr>
                <td>French</td>
                <td><code title="Key Value" class="key">'é'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td></td>
              </tr>
              <tr>
                <td>French</td>
                <td><code title="Key Value" class="key">'2'</code></td>
                <td><code title="Code Value" class="code">'Digit2'</code></td>
                <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              </tr>
            </tbody>
          </table>
          <p>Regardless of the current locale or the modifier key state, pressing the key labelled <code title="Character Value Glyph" class="glyph">'2'</code>
            on a US keyboard always results in <code title="Code Value" class="code">'Digit2'</code> in the <code>code</code> attribute.
            </p>
        </div><!-- Handling the 2 Key -->

        <div class="example" id="example-key-shift-2">
          <div class="example-title"></div>
          <p>Sequence of Keyboard Events : <code title="Key Value" class="key">'Shift'</code> and <code title="Key Value" class="key">'2'</code></p>
          <p>Compare the attribute values in the following two key event sequences. They both produce the
            <code title="Character Value Glyph" class="glyph">'@'</code> character on a US keyboard, but differ in the order in which the
            keys are released. In the first sequence, the order is:
              <code title="Key Value" class="key">'Shift'</code> (down),
              <code title="Key Value" class="key">'2'</code> (down),
              <code title="Key Value" class="key">'2'</code> (up),
              <code title="Key Value" class="key">'Shift'</code> (up).
            </p>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th>Keyboard Layout</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-code"><code>KeyboardEvent<br>code</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'ShiftLeft'</code></td>
              <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'@'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'Digit2'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'@'</code></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'@'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'Digit2'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'ShiftLeft'</code></td>
              <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
            </tr>
          </tbody></table>
          <p>In the second sequence, the Shift is released before the 2, resulting in the following event order:
            <code title="Key Value" class="key">'Shift'</code> (down),
            <code title="Key Value" class="key">'2'</code> (down),
            <code title="Key Value" class="key">'Shift'</code> (up),
            <code title="Key Value" class="key">'2'</code> (up).
            </p>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th>Keyboard Layout</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-code"><code>KeyboardEvent<br>code</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'ShiftLeft'</code></td>
              <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'@'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'Digit2'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'@'</code></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'ShiftLeft'</code></td>
              <td><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td>US</td>
              <td class="cell-center"><code title="Key Value" class="key">'2'</code></td>
              <td class="cell-center"><code title="Code Value" class="code">'Digit2'</code></td>
              <td></td>
            </tr>
          </tbody></table>
          <p>Note that the values contained in the <code>key</code> attribute does not match between
            the keydown and keyup events for the <code title="Character Value Glyph" class="glyph">'2'</code> key. The <code>code</code> attribute provides a consistent value
            that is not affected by the current modifier state.
            </p>
        </div><!-- Sequence of Keyboard Events: Shift and 2 -->
      </section>  <!-- code-examples -->

      <section property="bibo:hasPart" resource="#code-virtual-keyboards" typeof="bibo:Chapter" id="code-virtual-keyboards">
        <h4 resource="#h-code-virtual-keyboards" id="h-code-virtual-keyboards"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.2.4 </span><code>code</code> and Virtual Keyboards</span></h4>
        <p>The usefulness of the <code>code</code> attribute is less obvious for virtual keyboards (and also
          for remote controls and chording keyboards).
          In general, if a virtual (or remote control) keyboard is mimicking the layout and functionality
          of a standard keyboard, then it <em title="MUST" class="rfc2119">MUST</em> also set the <code>code</code> attribute as appropriate.
          For keyboards which are not mimicking the layout of a standard keyboard, then the <code>code</code>
          attribute <em title="MAY" class="rfc2119">MAY</em> be set to the closest match on a standard keyboard or it <em title="MAY" class="rfc2119">MAY</em> be left undefined.
          </p>
        <p>For virtual keyboards with keys that produce different values based on some modifier state,
          the <code>code</code> value should be the <code>key</code> value
          generated when the button is pressed while the device is in its factory-reset state.
          </p>
      </section>  <!-- code-virtual-keyboards -->

    </section>  <!-- keys-codevalues -->

    <section property="bibo:hasPart" resource="#keys-keyvalues" typeof="bibo:Chapter" id="keys-keyvalues">
      <h3 resource="#h-keys-keyvalues" id="h-keys-keyvalues"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3 </span>Keyboard Event <code>key</code> Values</span></h3>

      <p>A key value is a <code>DOMString</code> that can be used to indicate any given key on a keyboard, regardless of position or state, by the value it produces.  These
        key values <em title="MAY" class="rfc2119">MAY</em> be used as return values for keyboard events generated by the implementation, or as input values by the content author to specify desired input (such
        as for keyboard shortcuts).
        </p>

      <p>The list of valid <code>key</code> values is defined in the
        DOM Level 3 KeyboardEvent key Values Specification [<a href="#references-D3E-key">DOM3 key Values</a>].
        </p>

      <p>Key values can be used to detect the value of a key which has been pressed, using the <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>
        attribute.  Content authors can retrieve the <a class="def" href="#glossary-character-value">
        character value</a> of upper- or lower-case letters, number, symbols, or other character-producing keys, and also the <a class="def" href="#glossary-key-value">key
        value</a> of control keys, modifier keys, function keys, or other keys that do not generate characters. These values can be used for monitoring particular
        input strings, for detecting and acting on modifier key input in combination with other inputs (such as a mouse), for creating virtual keyboards, or for any number
        of other purposes.</p>

      <p>Key values can also be used by content authors in string comparisons, as values for markup attributes (such as the HTML <code>accesskey</code>) in conforming <a class="def" href="#glossary-host-language">host languages</a>, or for other related purposes.   A conforming <a class="def" href="#glossary-host-language">host language</a>
        <em title="SHOULD" class="rfc2119">SHOULD</em> allow content authors to use either of the two equivalent string values for a key value: the <a class="def" href="#glossary-character-value">character value</a>,
        or the <a class="def" href="#glossary-key-value">key value</a>.</p>

      <div class="note"><div id="h-note57" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> While implementations will use the most relevant value for a key independently of the platform or keyboard layout mappings,
        content authors can not make assumptions on the ability of keyboard devices to generate them.  When using keyboard events and key values for shortcut-key combinations,
        content authors can <q>consider using numbers and function keys (F4, F5, and so on) instead of letters</q> ([<cite><a class="informative" href="#references-DWW95">DWW95</a></cite>])
        given that most keyboard layouts will provide keys for those.</p></div>

      <p>A key value does not indicate a specific key on the physical keyboard, nor does it reflect the character printed on the key. A key
        value indicates the current value of the event with consideration to the current state of all active keys and key input modes
        (including shift modes), as reflected in the operating-system mapping of the keyboard and reported to the implementation.  In other
        words, the key value for the key marked <code title="Character Value Glyph" class="glyph">'O'</code> on a <a class="def" href="#glossary-qwerty">QWERTY</a> keyboard
        has the key value <code title="Key Value" class="key">'o'</code> in an unshifted state and <code title="Key Value" class="key">'O'</code> in a shifted state.
        Because a user can map their keyboard to an arbitrary custom configuration, the content author is encouraged not to assume that a
        relationship exists between the shifted and unshifted states of a key and the majuscule form (uppercase or capital letters)
        and minuscule form (lowercase or small letters) of a character representation, but is encouraged instead to use the value of the
        <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a> attribute. For example, the Standard "102" Keyboard layout
        depicted in [<a href="#references-D3E-code">DOM3 code Values</a>] illustrates one possible set of
        <a class="def" href="#glossary-key-mapping">key mappings</a> on one possible keyboard layout. Many others exist, both standard and
        idiosyncratic.</p>

      <div class="note"><div id="h-note58" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> To simplify <a class="def" href="#glossary-dead-key">dead key</a> support, when the operating-system
        mapping of the keyboard is handling a <a class="def" href="#glossary-dead-key">dead key</a> state, the current state of the dead
        key sequence is not reported via the <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a> attribute. Rather, a key value of
        <code title="Key Value" class="key">'Dead'</code> is reported. Instead, implementations generate <a href="#events-compositionevents">composition events</a>
        which contain the intermediate state of the dead key sequence reported via the
        <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a> attribute. As in the previous example, the key value for
        the key marked <code title="Character Value Glyph" class="glyph">'O'</code> on a <a class="def" href="#glossary-qwerty">QWERTY</a> keyboard has a
        <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a> value of <code title="Character Value" class="char">'ö'</code> in an unshifted
        state during a dead-key operation to add an umlaut diacritic, and <code title="Character Value" class="char">'Ö'</code> in a shifted state during a dead-key
        operation to add an umlaut diacritic.</p></div>

      <p>It is also important to note that there is not a one-to-one relationship between key event states and key values.  A particular key value might be associated with
        multiple keys. For example, many standard keyboards contain more than one key with the <code title="Key Value" class="key">'Shift'</code> key value (normally distinguished by the
        <a href="#widl-KeyboardEvent-location"><code>KeyboardEvent.location</code></a> values <a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_LEFT"><code class="constant-name">DOM_KEY_LOCATION_LEFT</code></a>
        and <a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_RIGHT"><code class="constant-name">DOM_KEY_LOCATION_RIGHT</code></a>) or <code title="Key Value" class="key">'8'</code> key value (normally
        distinguished by the <a href="#widl-KeyboardEvent-location"><code>KeyboardEvent.location</code></a> values
        <a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_STANDARD"><code class="constant-name">DOM_KEY_LOCATION_STANDARD</code></a>
        and <a href="#widl-KeyboardEvent-DOM_KEY_LOCATION_NUMPAD"><code class="constant-name">DOM_KEY_LOCATION_NUMPAD</code></a>), and user-configured
        custom keyboard layouts <em title="MAY" class="rfc2119">MAY</em> duplicate any key value in multiple key-state scenarios (note that <a href="#widl-KeyboardEvent-location"><code>KeyboardEvent.location</code></a>
        is intended for standard keyboard layouts, and cannot always indicate a meaningful distinction).</p>

      <p>Finally, the meaning of any given character representation is context-dependent and complex.  For example, in some contexts, the asterisk (star) glyph (<code title="Character Value Glyph" class="glyph">'*'</code>) represents a footnote or emphasis (when bracketing a passage of text). However, in some documents or executable programs it is equivalent
        to the mathematical multiplication operation, while in other documents or executable programs, that function is reserved for the multiplication symbol (<code title="Character Value Glyph" class="glyph">'×'</code>,
        Unicode value <code title="Character Value" class="char">'\u00D7'</code>) or the Latin small letter <code>'x'</code> (due to the lack of a multiplication key on many keyboards
        and the superficial resemblance of the glyphs <code title="Character Value Glyph" class="glyph">'×'</code> and <code title="Character Value Glyph" class="glyph">'x'</code>).  Thus, the semantic meaning or function of
        character representations is outside the scope of this specification.</p>

      <section property="bibo:hasPart" resource="#keys-unicode" typeof="bibo:Chapter" id="keys-unicode">
        <h4 resource="#h-keys-unicode" id="h-keys-unicode"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.1 </span>Key Values and Unicode</span></h4>

        <p>The <a class="def" href="#glossary-character-value">character values</a> described in this specification are Unicode [<a href="#references-Unicode">Unicode</a>]
          codepoints, and as such, have certain advantages.</p>

        <p>The most obvious advantage is that it allows the content author to use the full range of internationalized language functionality available in the implementation,
          regardless of the limitations of the text input devices on the system.  This opens up possibilities for virtual keyboards and Web-application-based <a class="def" href="#glossary-ime">input method editors</a>.</p>

        <p>Another benefit is that it allows the content author to utilize the Unicode general category properties programmatically.</p>

        <p>With legacy keyboard event attributes such as <code class="attribute-name">keyCode</code> and <code class="attribute-name">charCode</code>, content authors are forced to
          filter key input using cryptic, platform- and implementation-specific numeric codes, with poor internationalization, such as the following pseudocode:</p>

        <div class="example">
          <div class="example-title"></div>
<pre><code>if ( ( event.charCode == 45 || event.charCode == 36 ) ||
     ( event.charCode &gt;= 48 &amp;&amp; event.charCode &lt;= 57 ) ||
     ( event.charCode &gt;= 96 &amp;&amp; event.charCode &lt;= 105 ) ) {
   <span class="comment">// minus sign, dollar sign, and numeric characters from keyboard and numpad</span>
   <span class="comment">// ...</span>
}
else if ( ( event.charCode &gt;= 65 &amp;&amp; event.charCode &lt;= 90 ) ||
          ( event.charCode &gt;= 97 &amp;&amp; event.charCode &lt;= 122 ) ) {
   <span class="comment">// alphabetic characters from Latin character set, A-Z, a-z</span>
   <span class="comment">// ...</span>
}
else {
   <span class="comment">// ...</span>
}
</code></pre>
        </div>

        <p>With key values and regular expressions, however, content authors can support selective and intuitive ranges for key-based input, in a cross-platform manner with
          advanced internationalization support, such as the following pseudocode:</p>

        <div class="example">
          <div class="example-title"></div>
<pre><code>if ( event.key == "-" || event.key.match("\p{Sc}") || event.key.match("\p{N}") ) {
   <span class="comment">// minus sign, any currency symbol, and numeric characters (regardless of key location)</span>
   <span class="comment">// ...</span>
}
else if ( event.key.match("\p{L}") ) {
   <span class="comment">// alphabetic characters from any language, upper and lower case</span>
   <span class="comment">// ...</span>
}
else {
   <span class="comment">// ...</span>
}
</code></pre>
        </div>

        <p>In addition, because Unicode categorizes each assigned <a class="def" href="#glossary-unicode-code-point">code point</a> into a group of code points used by a particular
          human writing system, even more advanced capabilities are possible.</p>

        <div class="example">
          <div class="example-title"></div>
          <p>A content author can match characters from a particular human script (e.g., Tibetan) using a regular expression such as
          <code>\p{Tibetan}</code>, to filter out other characters, or discover if a <a class="def" href="#glossary-unicode-code-point">code point</a> is in
          a certain code block (range of code points), using a regular expression like <code>\p{InCyrillic}</code>.</p>
        </div>

        <p>To facilitate this, implementations <em title="SHOULD" class="rfc2119">SHOULD</em> support Unicode range detection using regular expressions, in a manner such as the Perl Compatible Regular Expressions
          (PCRE) [<a href="#references-pcre">PCRE</a>].</p>
      </section>  <!-- keys-unicode -->

      <section property="bibo:hasPart" resource="#keys-modifiers" typeof="bibo:Chapter" id="keys-modifiers">
        <h4 resource="#h-keys-modifiers" id="h-keys-modifiers"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.2 </span>Modifier keys</span></h4>

        <p>Keyboard input uses modifier keys to change the normal behavior of a key.
          Like other keys, modifier keys generate
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          and
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
          events, as shown in the example below.
          Some modifiers are activated while the key is being pressed down or maintained pressed such as
            <code title="Key Value" class="key">'Alt'</code>,
            <code title="Key Value" class="key">'Control'</code>,
            <code title="Key Value" class="key">'Shift'</code>,
            <code title="Key Value" class="key">'AltGraph'</code>,
          or
            <code title="Key Value" class="key">'Meta'</code>.
          Others modifiers are activated depending on their state such as
            <code title="Key Value" class="key">'CapsLock'</code>,
            <code title="Key Value" class="key">'NumLock'</code>,
          or
            <code title="Key Value" class="key">'ScrollLock'</code>.
          Change in the state happens when the modifier key is being pressed down.
          The
            <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
          interface provides convenient attributes for some common modifiers keys:
            <a href="#widl-KeyboardEvent-ctrlKey"><code>KeyboardEvent.ctrlKey</code></a>,
            <a href="#widl-KeyboardEvent-shiftKey"><code>KeyboardEvent.shiftKey</code></a>,
            <a href="#widl-KeyboardEvent-altKey"><code>KeyboardEvent.altKey</code></a>,
            <a href="#widl-KeyboardEvent-metaKey"><code>KeyboardEvent.metaKey</code></a>.
          Some operating systems simulate the
            <code title="Key Value" class="key">'AltGraph'</code>
          modifier key with the combination of the
            <code title="Key Value" class="key">'Alt'</code>
          and
            <code title="Key Value" class="key">'Control'</code>
          modifier keys.
          Implementations are encouraged to use the
            <code title="Key Value" class="key">'AltGraph'</code>
          modifier key.
          </p>

        <p>The following example describes a possible sequence of events associated with the generation of the Unicode character Q (Latin Capital Letter Q, <a class="def" href="#glossary-unicode-code-point">Unicode code point</a> <code title="Character Value" class="char">'\u0051'</code>) on a US keyboard using a US mapping:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th>Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>Latin Capital Letter Q</td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
              <td class="cell-center"></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>The following example describes an alternate sequence of keys to the example above, where the <code title="Key Value" class="key">'Shift'</code> key is released before the <code title="Key Value" class="key">'Q'</code> key.  The key value for the key labeled <code title="Character Value Glyph" class="glyph">'Q'</code> will revert to its unshifted value for the <a class="eventtype" href="#event-type-keyup">
          <code>keyup</code></a> event:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th>Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>Latin Capital Letter Q</td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
              <td class="cell-center"></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'q'</code></td>
              <td></td>
              <td>Latin Small Letter Q</td>
            </tr>
          </tbody></table>
        </div>

        <p>The following example describes a possible sequence of keys that does not generate a Unicode character (using the same configuration):</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th>Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'v'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td>Latin Small Letter V</td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td colspan="4"><em><abbr title="Number, Other">No</abbr> beforeinput or input events are generated.</em></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'v'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td>Latin Small Letter V</td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>The following example shows the sequence of events when both <code title="Key Value" class="key">'Shift'</code> and
          <code title="Key Value" class="key">'Control'</code> are pressed:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th>Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code>
                <code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'V'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code>
                <code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>Latin Capital Letter V</td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td colspan="4"><em><abbr title="Number, Other">No</abbr> beforeinput or input events are generated.</em></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'V'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code>
                <code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>Latin Capital Letter V</td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>For non-US keyboard layouts, the sequence of events is the same, but the value of the key is based on the current
          keyboard layout. The following example shows a sequence of events when an Arabic keyboard layout is used:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th>Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'ر'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td>Arabic Letter Reh</td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'ر'</code></td>
              <td><code class="attribute-name"><a href="#widl-MouseEvent-ctrlKey">ctrlKey</a></code></td>
              <td>Arabic Letter Reh</td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Control'</code></td>
              <td></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <div class="note"><div id="h-note59" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
          The value in the keydown and keyup events varies based on the current keyboard
          layout in effect when the key is pressed.
          This means that the <code title="Key Value" class="key">'v'</code> key on a US layout and the
          <code title="Key Value" class="key">'ر'</code> key on an Arabic layout will generate different
          events even though they are the same physical key.
          To identify these events as coming from the same physical key, you will need
          to make use of the <code>code</code> attribute.
          </p></div>

        <p>In some cases, modifier keys change the key value value for a key event.
          For example, on some MacOS keyboards, the  key labeled <code title="Character Value Glyph" class="glyph">'delete'</code>
          functions the same as the <code title="Key Value" class="key">'Backspace'</code> key on the
          Windows OS when unmodified, but when modified by the <code title="Key Value" class="key">'Fn'</code>
          key, acts as the <code title="Key Value" class="key">'Delete'</code> key, and the value of the
          key value will match the most appropriate function of the key in its current
          modified state.
          </p>

      </section>  <!-- keys-modifiers -->

      <section property="bibo:hasPart" resource="#keys-dead" typeof="bibo:Chapter" id="keys-dead">
        <h4 resource="#h-keys-dead" id="h-keys-dead"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.3 </span>Dead keys</span></h4>

        <p>Some keyboard input uses <a class="def" href="#glossary-dead-key">dead keys</a> for the input of composed character sequences. Unlike the handwriting sequence,
          in which users enter the base character first, keyboard input requires to enter a special state when a <a class="def" href="#glossary-dead-key">dead key</a> is
          pressed and emit the character(s) only when one of a limited number of <q>legal</q> base character is entered.</p>

        <div class="note"><div id="h-note60" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The MacOS and Linux operating systems use input methods to process
          <a class="def" href="#glossary-dead-key">dead keys</a>.
          </p></div>

        <p>The <a class="def" href="#glossary-dead-key">dead keys</a> (across all keyboard layouts and mappings) are represented by the
          key value <code title="Key Value" class="key">'Dead'</code>. In response to any dead key press, <a href="#events-compositionevents">
          composition events</a> must be dispatched by the user agent and the
          <a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a> event's
          <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a> value must be the character value of the current state
          of the dead key combining sequence.</p>

        <p>While Unicode combining characters always follow the handwriting sequence, with the
          combining character trailing the corresponding letter, typical dead key input <em title="MAY" class="rfc2119">MAY</em> reverse the sequence, with the
          combining character before the corresponding letter. For example, the word <em>naïve</em>, using the combining diacritic
          <em>¨</em>, would be represented sequentially in Unicode as <em>nai¨ve</em>, but <em title="MAY" class="rfc2119">MAY</em> be typed <em>na¨ive</em>. The sequence
          of keystrokes <code title="Character Value" class="char">'\u0302'</code> (Combining Circumflex Accent key) and <code title="Character Value" class="char">'\u0065'</code>
          (key marked with the Latin Small Letter E) will likely produce (on a French keyboard using a french mapping and without
          any modifier activated) the Unicode character <code title="Character Value Glyph" class="glyph">'ê'</code> (Latin Small Letter E With Circumflex), as
          preferred by the Unicode Normalization Form <em>NFC</em>:</p>

        <div class="note"><div id="h-note61" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> The <code>keydown</code> and <code>keyup</code> events shown in these
          examples would normally be suppressed during the composition session.
          They are included in these examples to make the user actions (pressing and releasing keys) more apparent.
          </p></div>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th class="cell-center"><a href="#widl-CompositionEvent-data"><code>CompositionEvent<br>data</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td>Combining Circumflex Accent (Dead Key)</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value" class="char">'\u0302'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'ê'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'ê'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">7.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'ê'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">8.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'e'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter E</td>
            </tr>
          </tbody></table>
        </div>

        <div class="note"><div id="h-note62" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> In the second <code>keydown</code> event (step 5), the key value
          (assuming the event is not suppressed) will
          <em>not</em> be <code title="Key Value" class="key">'e'</code> (Latin Small Letter E key) under normal circumstances
          because the value delivered to the user agent will already be modified by the dead key operation.</p></div>

        <p>This process might be aborted when a user types an unsupported base character (that is, a base character for which the which the active diacritical mark is not
          available) after pressing a <a class="def" href="#glossary-dead-key">dead key</a>:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th class="cell-center"><a href="#widl-CompositionEvent-data"><code>CompositionEvent<br>data</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td>Combining Circumflex Accent (Dead Key)</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value" class="char">'\u0302'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'q'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter Q</td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">7.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">8.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'q'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>
      </section>  <!-- keys-dead -->

      <section property="bibo:hasPart" resource="#keys-IME" typeof="bibo:Chapter" id="keys-IME">
        <h4 resource="#h-keys-ime" id="h-keys-ime"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.4 </span>Input Method Editors</span></h4>

        <p>This specification includes a model for <a class="def" href="#glossary-ime">input method editors (IMEs)</a>, through the <a href="#interface-CompositionEvent">CompositionEvent</a>
          interface and events.  However, Composition Events and Keyboard Events do not necessarily map as a one-to-one relationship.  As an example, receiving a <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> for the <code title="Key Value" class="key">'Accept'</code> key value does not necessarily imply
          that the text currently selected in the <a class="def" href="#glossary-ime">IME</a> is being accepted, but indicates only that a keystroke happened, disconnected
          from the <a class="def" href="#glossary-ime">IME</a> Accept functionality (which would normally result in a <a class="eventtype" href="#event-type-compositionend">
          <code>compositionend</code></a> event in most <a class="def" href="#glossary-ime">IME</a> systems).  Keyboard events cannot be used to determine the current
          state of the input method editor, which can be obtained through the <a href="#widl-CompositionEvent-data"><code>data</code></a> attribute of the <a href="#interface-CompositionEvent">
          CompositionEvent</a> interface.  Additionally, <a class="def" href="#glossary-ime">IME</a> systems and devices vary in their functionality, and in which keys
          are used for activating that functionality, such that the <code title="Key Value" class="key">'Convert'</code> and <code title="Key Value" class="key">'Accept'</code> keys <em title="MAY" class="rfc2119">MAY</em> be represented
          by other available keys. Keyboard events correspond to the events generated by the input device after the keyboard layout mapping.</p>

        <div class="note"><div id="h-note63" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>  In some implementations or system configurations, some key events, or their values, might be suppressed
          by the <a class="def" href="#glossary-ime">IME</a> in use.</p></div>

        <p>The following example describes a possible sequence of keys to generate the Unicode character <code title="Character Value Glyph" class="glyph">'市'</code> (Kanji character, part of CJK Unified Ideographs) using Japanese
          input methods. This example assumes that the input method editor is activated and in the Japanese-Romaji input mode. The keys <code title="Key Value" class="key">'Convert'</code>
          and <code title="Key Value" class="key">'Accept'</code> <em title="MAY" class="rfc2119">MAY</em> be replaced by others depending on the input device in use and the configuration of the IME, e.g., it can be respectively
          <code title="Character Value" class="char">'\u0020'</code> (Space key) and <code title="Key Value" class="key">'Enter'</code>.</p>

        <div class="note"><div id="h-note64" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> <code title="Character Value Glyph" class="glyph">'詩'</code> (<q>poem</q>) and <code title="Character Value Glyph" class="glyph">'市'</code> (<q>city</q>) are homophones, both
          pronounced し (<q>shi</q>), so the user needs to use the <code title="Key Value" class="key">'Convert'</code> key to select the proper option.</p></div>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th class="cell-center"><a href="#widl-CompositionEvent-data"><code>CompositionEvent<br>data</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'s'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter S</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'s'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'s'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'i'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter I</td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'し'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">7.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'i'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">8.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Convert</td>
            </tr>
            <tr>
              <td class="cell-number">9.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'詩'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">10.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">11.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Convert</td>
            </tr>
            <tr>
              <td class="cell-number">12.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'市'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">13.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">14.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Accept'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Accept</td>
            </tr>
            <tr>
              <td class="cell-number">15.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'市'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">16.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Accept'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>IME composition can also be canceled as in the following example, with conditions identical to the previous example.
          The key <code title="Key Value" class="key">'Cancel'</code> might also be replaced by others depending on the input device in use and
          the configuration of the IME, e.g., it could be <code title="Character Value" class="char">'\u001B'</code> (Escape key).</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-isComposing"><code>KeyboardEvent<br>isComposing</code></a></th>
              <th class="cell-center"><a href="#widl-CompositionEvent-data"><code>CompositionEvent<br>data</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'s'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter S</td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-compositionstart"><code>compositionstart</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'s'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'s'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'i'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Latin Small Letter I</td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'し'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">7.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'i'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">8.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Convert</td>
            </tr>
            <tr>
              <td class="cell-number">9.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'詩'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">10.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">11.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Convert</td>
            </tr>
            <tr>
              <td class="cell-number">12.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'市'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">13.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Convert'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">14.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Cancel'</code></td>
              <td class="cell-center"><code>true</code></td>
              <td class="cell-center"></td>
              <td>Cancel</td>
            </tr>
            <tr>
              <td class="cell-number">15.</td>
              <td><a class="eventtype" href="#event-type-compositionupdate"><code>compositionupdate</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">16.</td>
              <td><a class="eventtype" href="#event-type-compositionend"><code>compositionend</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code>''</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">17.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Cancel'</code></td>
              <td class="cell-center"><code>false</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <div class="note"><div id="h-note65" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Some <a class="def" href="#glossary-ime">input method editors</a> (such as on the MacOS operating system) might set an <a class="def" href="#glossary-empty-string">
          empty string</a> to the composition data attribute before canceling a composition.</p></div>

        <section property="bibo:hasPart" resource="#keys-IME-keys" typeof="bibo:Chapter" id="keys-IME-keys">
          <h5 resource="#h-keys-ime-keys" id="h-keys-ime-keys"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.4.1 </span>Input Method Editor mode keys</span></h5>

          <p>Some keys on certain devices are intended to activate <a class="def" href="#glossary-ime">input method editor</a> functionality, or to change the mode of an active
            <a class="def" href="#glossary-ime">input method editor</a>.  Custom keys for this purpose can be defined for different devices or language modes. The keys defined
            in this specification for this purpose are: <code>Alphanumeric</code>, <code>CodeInput</code>, <code>FinalMode</code>, <code>HangulMode</code>, <code>HanjaMode</code>,
            <code>Hiragana</code>, <code>JunjaMode</code>, <code>KanaMode</code>,
            <code>KanjiMode</code>, <code>Katakana</code>, and <code>RomanCharacters</code>.  When one of these keys is pressed, and no <a class="def" href="#glossary-ime">IME</a>
            is currently active, the appropriate <a class="def" href="#glossary-ime">IME</a> is expected to be activated in the mode indicated by the key (if available). If
            an <a class="def" href="#glossary-ime">IME</a> is already active when the key is pressed, the active <a class="def" href="#glossary-ime">IME</a> might change to
            the indicated mode, or a different <a class="def" href="#glossary-ime">IME</a> might be launched, or the might <em title="MAY" class="rfc2119">MAY</em> be ignored, on a device- and application-specific
            basis.</p>

          <p>This specification also defines other keys which are intended for operation specifically with <a class="def" href="#glossary-ime">input method editors</a>: <code>
            Accept</code>, <code>AllCandidates</code>, <code>Cancel</code>, <code>Convert</code>, <code>Compose</code>, <code>FullWidth</code>, <code>HalfWidth</code>, <code>NextCandidate</code>,
            <code>Nonconvert</code>, and <code>PreviousCandidate</code>.  The functions of these keys are not defined in this specification — refer to other resources for details
            on <a class="def" href="#glossary-ime">input method editor</a> functionality.</p>

          <div class="note"><div id="h-note66" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Keys with <a class="def" href="#glossary-ime">input method editor</a> functions are not restricted to that purpose, and can have other device- or implementation-specific
            purposes.</p></div>
        </section>  <!-- keys-IME-keys -->
      </section>  <!-- keys-IME -->

      <section property="bibo:hasPart" resource="#keys-cancelable-keys" typeof="bibo:Chapter" id="keys-cancelable-keys">
        <h4 resource="#h-keys-cancelable-keys" id="h-keys-cancelable-keys"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.5 </span>Default actions and cancelable keyboard events</span></h4>

        <p>Canceling the
            <a class="def" href="#glossary-default-action">default action</a>
          of a
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          event <em title="MUST NOT" class="rfc2119">MUST NOT</em> affect its respective
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
          event, but it <em title="MUST" class="rfc2119">MUST</em> prevent the respective
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
          and
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
          (and
            <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
          if supported) events from being generated.
          The following example describes a possible sequence of keys to generate the Unicode character
          Q (Latin Capital Letter Q) on a US keyboard using a US mapping:
          </p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="http://w3c.github.io/editing-explainer/input-events.html#widl-InputEvent-data"><code>InputEvent<br>data</code></a></th>
              <th class="cell-center">Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>The <a class="def" href="#glossary-default-action">default action</a> is
                prevented, e.g., by invoking <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>.
                </td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td></td>
              <td></td>
              <td></td>
              <td></td>
              <td><em><abbr title="Number, Other">No</abbr>
                  <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
                or
                  <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
                (or
                  <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>,
                if supported) events are generated</em>
                </td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>If the key is a modifier key, the keystroke <em title="MUST" class="rfc2119">MUST</em> still be taken into account for the modifiers states. The following example describes a possible sequence of keys
          to generate the Unicode character Q (Latin Capital Letter Q) on a US keyboard using a US mapping:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="http://w3c.github.io/editing-explainer/input-events.html#widl-InputEvent-data"><code>InputEvent<br>data</code></a></th>
              <th class="cell-center">Modifiers</th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td>The <a class="def" href="#glossary-default-action">default action</a> is
                prevented, e.g., by invoking <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>.
                </td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'Q'</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Q'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code class="attribute-name"><a href="#widl-MouseEvent-shiftKey">shiftKey</a></code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Shift'</code></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>

        <p>If the key is part of a sequence of several keystrokes, whether it is a <a class="def" href="#glossary-dead-key">dead key</a> or
          it is contributing to an Input Method Editor sequence, the keystroke <em title="MUST" class="rfc2119">MUST</em> be ignored (not taken into account) only if the
          <a class="def" href="#glossary-default-action">default action</a> is canceled on the
          <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event. Canceling a
          <a class="def" href="#glossary-dead-key">dead key</a> on a
          <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> event has no effect on
          <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a> or
          <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a> events.
          The following example uses the dead key <code title="Key Value" class="key">'Dead'</code> (<code title="Character Value" class="char">'\u0302'</code> Combining Circumflex
          Accent key) and <code title="Key Value" class="key">'e'</code> (<code title="Character Value" class="char">'\u0065'</code>, Latin Small Letter E key) on a French
          keyboard using a French mapping and without any modifier activated:</p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="http://w3c.github.io/editing-explainer/input-events.html#widl-InputEvent-data"><code>InputEvent<br>data</code></a></th>
              <th>Notes</th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"></td>
              <td>The <a class="def" href="#glossary-default-action">default action</a> is
                prevented, e.g., by invoking <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a>.
                </td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'Dead'</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'e'</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Character Value Glyph" class="glyph">'e'</code></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">6.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'e'</code></td>
              <td class="cell-center"></td>
              <td></td>
            </tr>
          </tbody></table>
        </div>
      </section>  <!-- keys-cancelable-keys -->

      <section property="bibo:hasPart" resource="#keys-guidelines" typeof="bibo:Chapter" id="keys-guidelines">
        <h4 resource="#h-keys-guidelines" id="h-keys-guidelines"><span property="xhv:role" resource="xhv:heading"><span class="secno">6.3.6 </span>Guidelines for selecting key values</span></h4>

        <p><strong>This section is normative.</strong></p>

        <p>To determine the appropriate key value for a key, use the following algorithm:
          </p>

        <ol class="algo" id="key-algorithm">
          <li>If there exists an appropriate character in the <a href="#keys-keyvalues">key values set</a>,
            then the
              <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>
            attribute <em title="MUST" class="rfc2119">MUST</em> be a string consisting of the <em>key value</em> of that character.
            </li>
          <li>If the key generates a printable character,
            and there exists an appropriate
              <a class="def" href="#glossary-unicode-code-point">Unicode code point</a>,
            then the
              <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>
            attribute <em title="MUST" class="rfc2119">MUST</em> be a string consisting of the <em>char value</em> of that character.
            </li>
          <li>If more than one key is being pressed and the key combination includes one or more modifier keys that result in the key
            no longer producing a printable character (e.g., <code title="Character Value Glyph" class="glyph">'Control'</code> + <code title="Character Value Glyph" class="glyph">'a'</code>),
            then the key value should be the printable key value that would have been
            produced if the key had been typed with the default keyboard layout
            with no modifier keys except for <code title="Key Value" class="key">'Shift'</code> and <code title="Key Value" class="key">'AltGr'</code> applied.
            </li>
          <li>Otherwise, the special value <code title="Key Value" class="key">'Unidentified'</code> should be used.
            </li>
        </ol>

        <div class="example">
          <div class="example-title"></div>
          <ul>
            <li>On a US keyboard with a right-handed single-hand Dvorak
                <a class="def" href="#glossary-key-mapping">key mapping</a>,
              the key labeled
                <code title="Character Value Glyph" class="glyph">'Q'</code>
              maps to the key values
                <code title="Key Value" class="key">'5'</code> (unmodified)
              and
                <code title="Key Value" class="key">'%'</code> (shifted).
              The primary function of this key is to generate the character
                <code title="Key Value" class="key">'5'</code> (<code title="Character Value" class="char">'\u0035'</code>).
              Since this character is a character (in Unicode general category
              <abbr title="Number, Decimal Digit">Nd</abbr>), the
                <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>
              attribute value for the unmodified key will be <code title="Key Value" class="key">'5'</code>.
              </li>
            <li>On the same US Dvorak keyboard layout as the previous example,
              pressing <code title="Character Value Glyph" class="glyph">'Control'</code> and the key labeled <code title="Character Value Glyph" class="glyph">'Q'</code>
              will produce a key value of <code title="Key Value" class="key">'q'</code>.
              </li>
            <li>On a French PC keyboard with a standard French mapping, the primary function of the
                <code title="Character Value Glyph" class="glyph">'^'</code>
              key is to act as a
                <a class="def" href="#glossary-dead-key">dead key</a>
              for the combining circumflex diacritical mark.
              The value for this key is <code title="Key Value" class="key">'Dead'</code>.
              </li>
            <li>Also on a French PC keyboard with a standard French mapping, the
                <code title="Character Value Glyph" class="glyph">'é'</code>
              key (which corresponds to the <code title="Character Value Glyph" class="glyph">'2'</code> key on a US keyboard)
              generates a key value of <code title="Key Value" class="key">'é'</code> (<code title="Character Value" class="char">'\u00e9'</code>).
              </li>
            <li>On a Korean PC keyboard with a standard Korean mapping, the primary function of the
                <code title="Character Value Glyph" class="glyph">'Ha/En'</code>
              key is to switch between Hangul and English input.
              The predefined key value list has an appropriate entry for this key,
                <code title="Key Value" class="key">'HangulMode'</code>,
              so this will be the key value.
              </li>
            <li>On some mobile devices, there are special keys to launch specific applications.
              For a standard application like Calendar, there is a predefined key value of
                <code title="Key Value" class="key">'LaunchCalendar'</code>.
              </li>
          </ul>
        </div>

        <p>While every attempt has been made to make this list of key values as complete as possible, new key values
          will periodically need to be defined as new input devices are introduced.
          Rather than allowing user agents to define their own key values (which may not work across multiple user
          agents), bugs should be filed so that this specification can be updated.
          </p>

      </section>  <!-- keys-guidelines -->
    </section>  <!-- keys-keyvalues -->

  </section>  <!-- keys -->

  <!-- Appendix A: Legacy Event Initializers ========================================================-->
  <section property="bibo:hasPart" resource="#legacy-event-initializers" typeof="bibo:Chapter" id="legacy-event-initializers" class="appendix">
    <!--OddPage--><h2 resource="#h-legacy-event-initializers" id="h-legacy-event-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A. </span>Legacy Event Initializers</span></h2>

    <p><em>This section is informative</em></p>

    <p>Early versions of this specification included an initialization method on the
      interface (for example <code>initMouseEvent</code>) that required a long list of parameters
      that, in most cases, did not fully initialize all attributes of the event object.
      Because of this, event interfaces which were derived from the basic <code>Event</code> interface
      required that the initializer of <em>each</em> of the derived
      interfaces be called explicitly in order to fully initialize an event.
      </p>

    <div class="example">
      <div class="example-title"></div>
      <p>Initializing all the attributes of a MutationEvent requires calls to two initializer methods:
        <code>initEvent</code> and <code>initMutationEvent</code>.
        </p>
    </div>

    <p>Due in part to the length of time in the development of this standard, some implementations <em title="MAY" class="rfc2119">MAY</em> have
      taken a dependency on these (now deprecated) initializer methods.
      For completeness, these legacy event intializers are described in this Appendix.
      </p>

    <section property="bibo:hasPart" resource="#legacy-event-initializer-interfaces" typeof="bibo:Chapter" id="legacy-event-initializer-interfaces">
      <h3 resource="#h-legacy-event-initializer-interfaces" id="h-legacy-event-initializer-interfaces"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1 </span>Legacy Event Initializer Interfaces</span></h3>
      <p><em>This section is informative</em></p>

      <p>This section documents legacy initializer methods that were introduced in earlier
        versions of this specification.
        </p>

      <section property="bibo:hasPart" resource="#idl-interface-CustomEvent-initializers" typeof="bibo:Chapter" id="idl-interface-CustomEvent-initializers">
        <h4 resource="#h-idl-interface-customevent-initializers" id="h-idl-interface-customevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.1 </span>Initializers for interface CustomEvent</span></h4>

        <pre class="idl"><span class="idlInterface" id="idl-def-CustomEvent">partial interface <span class="idlInterfaceID">CustomEvent</span> {
<span class="idlSectionComment">    // Originally introduced (and deprecated) in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-CustomEvent-initCustomEvent">initCustomEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType">any</span> <span class="idlParamName">detailArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-2" typeof="bibo:Chapter" id="methods-2"><h5 resource="#h-methods-2" id="h-methods-2"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.1.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-CustomEvent-initCustomEvent-dup"><code>initCustomEvent</code></dt><dd>
            <p>Initializes attributes of a <code>CustomEvent</code> object. This method has the
              same behavior as <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initCustomEvent</code> method is deprecated.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">detailArg</td><td class="prmType"><code>any</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-CustomEvent-detail"><code>CustomEvent.detail</code></a>.</p></td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-CustomEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-UIEvent-initializers" typeof="bibo:Chapter" id="idl-interface-UIEvent-initializers">
        <h4 resource="#h-idl-interface-uievent-initializers" id="h-idl-interface-uievent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.2 </span>Initializers for interface UIEvent</span></h4>

        <pre class="idl"><span class="idlInterface" id="idl-def-UIEvent-1">partial interface <span class="idlInterfaceID">UIEvent</span> {
<span class="idlSectionComment">    // Deprecated in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-UIEvent-initUIEvent">initUIEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">detailArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-3" typeof="bibo:Chapter" id="methods-3"><h5 resource="#h-methods-3" id="h-methods-3"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.2.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-UIEvent-initUIEvent"><code>initUIEvent</code></dt><dd>
            <p>Initializes attributes of an <code>UIEvent</code> object.
              This method has the same behavior as <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initUIEvent</code> method is deprecated, but supported for
              backwards-compatibility with widely-deployed implementations.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-UIEvent-view"><code>UIEvent.view</code></a>. This value <em title="MAY" class="rfc2119">MAY</em> be <code>null</code>.</p>
              </td></tr><tr><td class="prmName">detailArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-UIEvent-detail"><code>UIEvent.detail</code></a>.</p>
              </td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-UIEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-FocusEvent-initializers" typeof="bibo:Chapter" id="idl-interface-FocusEvent-initializers">
        <h4 resource="#h-idl-interface-focusevent-initializers" id="h-idl-interface-focusevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.3 </span>Initializers for interface FocusEvent</span></h4>

        <pre class="idl"><span class="idlInterface" id="idl-def-FocusEvent-1">partial interface <span class="idlInterfaceID">FocusEvent</span> {
<span class="idlSectionComment">    // Originally introduced (and deprecated) in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-FocusEvent-initFocusEvent">initFocusEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">detailArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span> <span class="idlParamName">relatedTargetArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-4" typeof="bibo:Chapter" id="methods-4"><h5 resource="#h-methods-4" id="h-methods-4"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.3.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-FocusEvent-initFocusEvent"><code>initFocusEvent</code></dt><dd>
            <p>Initializes attributes of a <code>FocusEvent</code> object.
              This method has the same behavior as
              <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initFocusEvent</code> method is deprecated.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">detailArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">relatedTargetArg</td><td class="prmType"><code><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-FocusEvent-relatedTarget"><code>FocusEvent.relatedTarget</code></a>. This value <em title="MAY" class="rfc2119">MAY</em> be <code>null</code>.</p></td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-FocusEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-MouseEvent-initializers" typeof="bibo:Chapter" id="idl-interface-MouseEvent-initializers">
        <h4 resource="#h-idl-interface-mouseevent-initializers" id="h-idl-interface-mouseevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.4 </span>Initializers for interface MouseEvent</span></h4>

        <pre class="idl"><span class="idlInterface" id="idl-def-MouseEvent-1">partial interface <span class="idlInterfaceID">MouseEvent</span> {
<span class="idlSectionComment">    // Deprecated in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-MouseEvent-initMouseEvent">initMouseEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">detailArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">screenXArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">screenYArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">clientXArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">clientYArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">ctrlKeyArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">altKeyArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">shiftKeyArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">metaKeyArg</span></span>, <span class="idlParam"><span class="idlParamType">short</span> <span class="idlParamName">buttonArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span> <span class="idlParamName">relatedTargetArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-5" typeof="bibo:Chapter" id="methods-5"><h5 resource="#h-methods-5" id="h-methods-5"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.4.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-MouseEvent-initMouseEvent"><code>initMouseEvent</code></dt><dd>
            <p>Initializes attributes of a <code>MouseEvent</code> object.
              This method has the same behavior as <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initMouseEvent</code> method is deprecated, but supported for
              backwards-compatibility with widely-deployed implementations.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">detailArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">screenXArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-screenX"><code>MouseEvent.screenX</code></a>.</p>
              </td></tr><tr><td class="prmName">screenYArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-screenY"><code>MouseEvent.screenY</code></a>.</p>
              </td></tr><tr><td class="prmName">clientXArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-clientX"><code>MouseEvent.clientX</code></a>.</p>
              </td></tr><tr><td class="prmName">clientYArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-clientY"><code>MouseEvent.clientY</code></a>.</p>
              </td></tr><tr><td class="prmName">ctrlKeyArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-ctrlKey"><code>MouseEvent.ctrlKey</code></a>.</p>
              </td></tr><tr><td class="prmName">altKeyArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-altKey"><code>MouseEvent.altKey</code></a>.</p>
              </td></tr><tr><td class="prmName">shiftKeyArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-shiftKey"><code>MouseEvent.shiftKey</code></a>.</p>
              </td></tr><tr><td class="prmName">metaKeyArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-metaKey"><code>MouseEvent.metaKey</code></a>.</p>
              </td></tr><tr><td class="prmName">buttonArg</td><td class="prmType"><code>short</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-button"><code>MouseEvent.button</code></a>.</p>
              </td></tr><tr><td class="prmName">relatedTargetArg</td><td class="prmType"><code><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MouseEvent-relatedTarget"><code>MouseEvent.relatedTarget</code></a>. This value <em title="MAY" class="rfc2119">MAY</em> be <code>null</code>.</p>
              </td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-MouseEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-WheelEvent-initializers" typeof="bibo:Chapter" id="idl-interface-WheelEvent-initializers">
        <h4 resource="#h-idl-interface-wheelevent-initializers" id="h-idl-interface-wheelevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.5 </span>Initializers for interface WheelEvent</span></h4>

        <pre class="idl"><span class="idlInterface" id="idl-def-WheelEvent-1">partial interface <span class="idlInterfaceID">WheelEvent</span> {
<span class="idlSectionComment">    // Originally introduced (and deprecated) in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-WheelEvent-initWheelEvent">initWheelEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">detailArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">screenXArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">screenYArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">clientXArg</span></span>, <span class="idlParam"><span class="idlParamType">long</span> <span class="idlParamName">clientYArg</span></span>, <span class="idlParam"><span class="idlParamType">short</span> <span class="idlParamName">buttonArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#interface-EventTarget">EventTarget</a>?</span> <span class="idlParamName">relatedTargetArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">modifiersListArg</span></span>, <span class="idlParam"><span class="idlParamType">double</span> <span class="idlParamName">deltaXArg</span></span>, <span class="idlParam"><span class="idlParamType">double</span> <span class="idlParamName">deltaYArg</span></span>, <span class="idlParam"><span class="idlParamType">double</span> <span class="idlParamName">deltaZArg</span></span>, <span class="idlParam"><span class="idlParamType">unsigned long</span> <span class="idlParamName">deltaMode</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-6" typeof="bibo:Chapter" id="methods-6"><h5 resource="#h-methods-6" id="h-methods-6"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.5.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-WheelEvent-initWheelEvent"><code>initWheelEvent</code></dt><dd>
            <p>Initializes attributes of a <code>WheelEvent</code> object.
              This method has the same behavior as
              <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initWheelEvent</code> method is deprecated.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">detailArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">screenXArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">screenYArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">clientXArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">clientYArg</td><td class="prmType"><code>long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">buttonArg</td><td class="prmType"><code>short</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">relatedTargetArg</td><td class="prmType"><code><a class="internalDFN" href="#interface-EventTarget">EventTarget</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-MouseEvent-initMouseEvent"><code>MouseEvent.initMouseEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">modifiersListArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>A <a class="normative" href="http://www.w3.org/TR/2004/REC-xml-20040204/#NT-S"><em>white space</em></a>
                  separated list of modifier key values to be activated on this object.
                  As an example, <code>"Control Shift"</code> marks the control and shift modifiers as activated
                  (the <a href="#widl-MouseEvent-ctrlKey"><code>MouseEvent.ctrlKey</code></a> and
                  <a href="#widl-MouseEvent-shiftKey"><code>MouseEvent.shiftKey</code></a> inherited attributes
                  will be <code>true</code> on the initialized <code>WheelEvent</code> object).
                  </p>
              </td></tr><tr><td class="prmName">deltaXArg</td><td class="prmType"><code>double</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-WheelEvent-deltaX"><code>WheelEvent.deltaX</code></a>.</p></td></tr><tr><td class="prmName">deltaYArg</td><td class="prmType"><code>double</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-WheelEvent-deltaY"><code>WheelEvent.deltaY</code></a>.</p></td></tr><tr><td class="prmName">deltaZArg</td><td class="prmType"><code>double</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-WheelEvent-deltaZ"><code>WheelEvent.deltaZ</code></a>.</p></td></tr><tr><td class="prmName">deltaMode</td><td class="prmType"><code>unsigned long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-WheelEvent-deltaMode"><code>WheelEvent.deltaMode</code></a>.</p></td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-WheelEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-KeyboardEvent-initializers" typeof="bibo:Chapter" id="idl-interface-KeyboardEvent-initializers">
        <h4 resource="#h-idl-interface-keyboardevent-initializers" id="h-idl-interface-keyboardevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.6 </span>Initializers for interface KeyboardEvent</span></h4>
        <div class="note"><div id="h-note67" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>The argument list to this legacy KeyboardEvent initializer does not include
          the <code>detailArg</code> (present in other initializers) and adds the <code>locale</code> argument (see
          <a href="#changes-drafts">Changes between different drafts of this specification</a>); it is necessary
          to preserve this inconsistency for compatibility with existing implementations.</p></div>
        <pre class="idl"><span class="idlInterface" id="idl-def-KeyboardEvent-1">partial interface <span class="idlInterfaceID">KeyboardEvent</span> {
<span class="idlSectionComment">    // Originally introduced (and deprecated) in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-KeyboardEvent-initKeyboardEvent">initKeyboardEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">keyArg</span></span>, <span class="idlParam"><span class="idlParamType">unsigned long</span> <span class="idlParamName">locationArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">modifiersListArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">repeat</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">locale</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-7" typeof="bibo:Chapter" id="methods-7"><h5 resource="#h-methods-7" id="h-methods-7"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.6.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-KeyboardEvent-initKeyboardEvent"><code>initKeyboardEvent</code></dt><dd>
            <p>Initializes attributes of a <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> object.
              This method has the same behavior as <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a>.
              The value of <a href="#widl-UIEvent-detail"><code>UIEvent.detail</code></a> remains undefined.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initKeyboardEvent</code> method is deprecated.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">keyArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>.</p></td></tr><tr><td class="prmName">locationArg</td><td class="prmType"><code>unsigned long</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-KeyboardEvent-location"><code>KeyboardEvent.location</code></a>.</p></td></tr><tr><td class="prmName">modifiersListArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>A <a class="normative" href="http://www.w3.org/TR/2004/REC-xml-20040204/#NT-S"><em>white space</em></a>
                separated list of modifier key values to be activated on this object.
                As an example, <code>"Control Alt"</code> marks the control and alt modifiers as activated.
                </p>
              </td></tr><tr><td class="prmName">repeat</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies whether the key event is repeating. See <a href="#widl-KeyboardEvent-repeat"><code>KeyboardEvent.repeat</code></a>.</p></td></tr><tr><td class="prmName">locale</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies the <code>locale</code> attribute of the KeyboardEvent.
                </p><div class="issue"><div id="h-issue2" role="heading" aria-level="6" class="issue-title"><span>Issue 2</span></div><p class="">Should we include locale in this specification now?</p></div></td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-KeyboardEvent-initializers -->

      <section property="bibo:hasPart" resource="#idl-interface-CompositionEvent-initializers" typeof="bibo:Chapter" id="idl-interface-CompositionEvent-initializers">
        <h4 resource="#h-idl-interface-compositionevent-initializers" id="h-idl-interface-compositionevent-initializers"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.7 </span>Initializers for interface CompositionEvent</span></h4>
        <div class="note"><div id="h-note68" role="heading" aria-level="5" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>The argument list to this legacy CompositionEvent initializer does not include
          the <code>detailArg</code> (present in other initializers) and adds the <code>locale</code> argument (see
          <a href="#changes-drafts">Changes between different drafts of this specification</a>); it is necessary
          to preserve this inconsistency for compatibility with existing implementations.</p></div>
        <pre class="idl"><span class="idlInterface" id="idl-def-CompositionEvent-1">partial interface <span class="idlInterfaceID">CompositionEvent</span> {
<span class="idlSectionComment">    // Originally introduced (and deprecated) in this specification</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-CompositionEvent-initCompositionEvent">initCompositionEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType"><a class="internalDFN" href="#dfn-window">Window</a>?</span> <span class="idlParamName">viewArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">dataArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">locale</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#methods-8" typeof="bibo:Chapter" id="methods-8"><h5 resource="#h-methods-8" id="h-methods-8"><span property="xhv:role" resource="xhv:heading"><span class="secno">A.1.7.1 </span>Methods</span></h5><dl class="methods"><dt id="widl-CompositionEvent-initCompositionEvent"><code>initCompositionEvent</code></dt><dd>
            <p>Initializes attributes of a <code>CompositionEvent</code> object.
              This method has the same behavior as <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a>.
              The value of <a href="#widl-UIEvent-detail"><code>UIEvent.detail</code></a> remains undefined.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <code>initCompositionEvent</code> method is deprecated.
              </p></div>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">viewArg</td><td class="prmType"><code><a class="internalDFN" href="#dfn-window">Window</a></code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Refer to the <a href="#widl-UIEvent-initUIEvent"><code>UIEvent.initUIEvent()</code></a> method for a description of this parameter.</p></td></tr><tr><td class="prmName">dataArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies <a href="#widl-CompositionEvent-data"><code>CompositionEvent.data</code></a>.</p></td></tr><tr><td class="prmName">locale</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc"><p>Specifies the <code>locale</code> attribute of the CompositionEvent.
                  </p><div class="issue"><div id="h-issue3" role="heading" aria-level="6" class="issue-title"><span>Issue 3</span></div><p class="">Should we include locale in this specification now?</p></div>
                </td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section>
      </section>  <!-- idl-interface-CompositionEvent-initializers -->

    </section>  <!-- legacy-event-initializer-interfaces -->
  </section>  <!-- legacy-event-initializers -->

  <!-- Appendix B: Legacy Key Attributes ========================================================-->
  <section property="bibo:hasPart" resource="#legacy-key-attributes" typeof="bibo:Chapter" id="legacy-key-attributes">
    <!--OddPage--><h2 resource="#h-legacy-key-attributes" id="h-legacy-key-attributes"><span property="xhv:role" resource="xhv:heading"><span class="secno">B. </span>Legacy Key Attributes</span></h2>
    <p><em>This section is informative</em></p>

    <p>This section provides a non-normative description of the attributes that are currently used when
      handling keyboard events.
      </p>

    <p>These features were never formally specified and the current browser implementations vary in
      significant ways.
      The large amount of legacy content, including script libraries, that relies upon detecting the
      <a class="def" href="#glossary-user-agent">user agent</a> and acting accordingly means that any
      attempt to formalize these legacy attributes and events would risk breaking as much content as
      it would fix or enable.
      Additionally, these attributes are not suitable for international usage, nor do they address
      accessibility concerns.
      </p>

    <p>Therefore, this specification does not normatively define the events and attributes commonly employed
      for handling keyboard input, though they <em title="MAY" class="rfc2119">MAY</em> be present in
      <a class="def" href="#glossary-user-agent">user agents</a> for compatibility with legacy content.
      Authors <em title="SHOULD" class="rfc2119">SHOULD</em> use the <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a> attribute
      instead of the <code class="attribute-name">charCode</code>
      and <code class="attribute-name">keyCode</code> attributes.
      </p>

    <p>However, for the purpose of documenting the current state of these features and their relation to
      normative events and attributes, this section provides an informative description.
      For implementations which do support these attributes and events, it is suggested that the definitions
      provided in this section be used.
      </p>

    <section property="bibo:hasPart" resource="#KeyboardEvent-supplemental-interface" typeof="bibo:Chapter" id="KeyboardEvent-supplemental-interface">
      <h3 resource="#h-keyboardevent-supplemental-interface" id="h-keyboardevent-supplemental-interface"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.1 </span>Legacy <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> supplemental interface</span></h3>
      <p><em>This section is informative</em></p>

      <p>Browser support for keyboards has traditionally relied on three ad-hoc attributes,
        <code class="attribute-name">keyCode</code>, <code class="attribute-name">charCode</code>,
        and <code class="attribute-name">which</code>.</p>

      <p>All three of these attributes return a numerical code that represents some aspect of the key pressed:
        <code class="attribute-name">keyCode</code> is an index of the key itself.
        <code class="attribute-name">charCode</code> is the <abbr title="American Standard Code for Information Interchange">ASCII</abbr> value of the character keys.
        <code class="attribute-name">which</code> is the character value where available and otherwise the key index.
        The values for these attributes, and the availability of the attribute, is inconsistent across
        platforms, keyboard languages and layouts, <a class="def" href="#glossary-user-agent">user agents</a>,
        versions, and even event types.
        </p>

      <dl>
        <dt id="events-KeyboardEvent-supplemental"><strong>Interface <em>KeyboardEvent (supplemental)</em></strong></dt>
        <dd>
          <p class="intro-dom">Introduced in this specification</p>

          <p>The partial
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
            interface is an informative extension of the
              <a href="#interface-KeyboardEvent">KeyboardEvent</a>
            interface, which adds the
              <a href="#widl-KeyboardEvent-charCode">charCode</a>,
              <a href="#widl-KeyboardEvent-keyCode">keyCode</a>,
              and <a href="#widl-KeyboardEvent-which">which</a>
            attributes.</p>

          <p>The partial
              <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
            interface can be obtained by using the
              <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("KeyboardEvent")</code></a>
            method call in implementations that support this extension.</p>

          <pre class="idl"><span class="idlInterface" id="idl-def-KeyboardEvent-2">partial interface <span class="idlInterfaceID">KeyboardEvent</span> {
<span class="idlSectionComment">    // The following support legacy user agents</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned long</span> <span class="idlAttrName"><a href="#widl-KeyboardEvent-charCode">charCode</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned long</span> <span class="idlAttrName"><a href="#widl-KeyboardEvent-keyCode">keyCode</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned long</span> <span class="idlAttrName"><a href="#widl-KeyboardEvent-which">which</a></span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-7" typeof="bibo:Chapter"><h4 resource="#attributes-7" id="attributes-7"><span property="xhv:role" resource="xhv:heading">Attributes</span></h4><dl class="attributes"><dt id="widl-KeyboardEvent-charCode"><code>charCode</code> of type <span class="idlAttrType">unsigned long</span>, readonly   </dt><dd>
              <p><code class="attribute-name">charCode</code> holds a character value, for
                <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> events which
                generate character input.
                The value is the Unicode reference number (code point) of that character (e.g.
                <code>event.charCode = event.key.charCodeAt(0)</code> for printable characters).
                For <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> or
                <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events, the
                value of <code class="attribute-name">charCode</code> is <code>0</code>.
                </p>
            </dd><dt id="widl-KeyboardEvent-keyCode"><code>keyCode</code> of type <span class="idlAttrType">unsigned long</span>, readonly   </dt><dd>
              <p><code class="attribute-name">keyCode</code> holds a system- and implementation-dependent
                numerical code signifying the unmodified identifier associated with the key pressed.
                Unlike the <a href="#widl-KeyboardEvent-key"><code>KeyboardEvent.key</code></a>
                attribute, the set of possible values are not normatively defined in this specification.
                Typically, these value of the <code class="attribute-name">keyCode</code>
                <em title="SHOULD" class="rfc2119">SHOULD</em> represent the decimal codepoint in
                <abbr title="American Standard Code for Information Interchange">ASCII</abbr> [<a href="#ref-rfc20">RFC20</a>][<a href="#ref-US-ASCII">US-<abbr title="American Standard Code for Information Interchange">ASCII</abbr></a>]
                or Windows 1252 [<a href="#ref-WIN1252">WIN1252</a>],
                but <em title="MAY" class="rfc2119">MAY</em> be drawn from a different appropriate character set.
                Implementations that are unable to identify a key use the key value
                <code title="Key Value" class="key">'0'</code>.
                </p>

              <p>See <a href="#legacy-key-models">Legacy key models</a> for more details on how to
                determine the values for <code class="attribute-name">keyCode</code>.
                </p>
            </dd><dt id="widl-KeyboardEvent-which"><code>which</code> of type <span class="idlAttrType">unsigned long</span>, readonly   </dt><dd>
              <p><code>which</code> holds a system- and implementation-dependent numerical code
                signifying the unmodified identifier associated with the key pressed.
                In most cases, the value is identical to
                <code class="attribute-name"><a href="#widl-KeyboardEvent-keyCode">keyCode</a></code>.
                </p>
            </dd></dl></section>

        </dd>
      </dl>

      <dl>
        <dt id="events-KeyboardEventInit-supplemental"><strong>dictionary <em>KeyboardEventInit (supplemental)</em></strong></dt>
        <dd>
          <p>Browsers that include support for
              <code class="attribute-name">keyCode</code>,
              <code class="attribute-name">charCode</code>,
            and
              <code class="attribute-name">which</code>
            in <code>KeyboardEvent</code> should also add the following members to the
            <code>KeyboardEventInit</code> dictionary.
            </p>

          <p>The partial
              <a href="#interface-KeyboardEvent"><code>KeyboardEventInit</code></a>
            dictionary is an informative extension of the
              <a href="#interface-KeyboardEvent">KeyboardEventInit</a>
            dictionary, which adds
              <a href="#widl-KeyboardEvent-charCode">charCode</a>,
              <a href="#widl-KeyboardEvent-keyCode">keyCode</a>,
              and <a href="#widl-KeyboardEvent-which">which</a>
            members to initialize the corresponding <code>KeyboardEvent</code> attributes.</p>

          <pre class="idl"><span class="idlDictionary" id="idl-def-KeyboardEventInit-dup">partial dictionary <span class="idlDictionaryID">KeyboardEventInit</span> {
<span class="idlMember">    <span class="idlMemberType">unsigned long</span> <span class="idlMemberName"><a href="#widl-KeyboardEventInit-charCode">charCode</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">unsigned long</span> <span class="idlMemberName"><a href="#widl-KeyboardEventInit-keyCode">keyCode</a></span> = <span class="idlMemberValue">0</span>;</span>
<span class="idlMember">    <span class="idlMemberType">unsigned long</span> <span class="idlMemberName"><a href="#widl-KeyboardEventInit-which">which</a></span> = <span class="idlMemberValue">0</span>;</span>
};</span></pre><section property="bibo:hasPart" resource="#dictionary-keyboardeventinit-members-1" typeof="bibo:Chapter"><h4 resource="#dictionary-keyboardeventinit-members-1" id="dictionary-keyboardeventinit-members-1"><span property="xhv:role" resource="xhv:heading">Dictionary <a href="#idl-def-KeyboardEventInit" class="idlType"><code>KeyboardEventInit</code></a> Members</span></h4><dl class="dictionary-members"><dt id="widl-KeyboardEventInit-charCode"><code>charCode</code> of type <span class="idlMemberType">unsigned long</span>, defaulting to <code>0</code></dt><dd>
              <p>Initializes the <code class="attribute-name">charCode</code> attribute of the
                KeyboardEvent to the Unicode code point for the event's character.
                </p>
            </dd><dt id="widl-KeyboardEventInit-keyCode"><code>keyCode</code> of type <span class="idlMemberType">unsigned long</span>, defaulting to <code>0</code></dt><dd>
              <p>Initializes the <code class="attribute-name">keyCode</code> attribute of the
                KeyboardEvent to the system- and implementation-dependent
                numerical code signifying the unmodified identifier associated with the key pressed.
                </p>
            </dd><dt id="widl-KeyboardEventInit-which"><code>which</code> of type <span class="idlMemberType">unsigned long</span>, defaulting to <code>0</code></dt><dd>
              <p>Initializes the <code>which</code> attribute of the KeyboardEvent
                to the implementation-dependent numerical code
                signifying the unmodified identifier associated with the key pressed.
                In most cases, the value is identical to
                <code class="attribute-name"><a href="#widl-KeyboardEvent-keyCode">keyCode</a></code>.
                </p>
            </dd></dl></section>
        </dd>
      </dl>

    </section>

    <section property="bibo:hasPart" resource="#legacy-key-models" typeof="bibo:Chapter" id="legacy-key-models">
      <h3 resource="#h-legacy-key-models" id="h-legacy-key-models"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.2 </span>Legacy key models</span></h3>
      <p><em>This section is informative</em></p>

      <p>Implementations differ on which values are exposed on these attributes for different event types.
        An implementation <em title="MAY" class="rfc2119">MAY</em> choose to expose both virtual key codes and character codes in the
        <code class="attribute-name">keyCode</code> property (<em>conflated model</em>), or report
        separate <code class="attribute-name">keyCode</code> and <code class="attribute-name">charCode</code>
        properties (<em>split model</em>).
        </p>

      <section property="bibo:hasPart" resource="#determine-keydown-keyup-keyCode" typeof="bibo:Chapter" id="determine-keydown-keyup-keyCode">
        <h4 resource="#h-determine-keydown-keyup-keycode" id="h-determine-keydown-keyup-keycode"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.2.1 </span>How to determine <code class="attribute-name">keyCode</code> for <code>keydown</code> and <code>keyup</code> events</span></h4>

        <p>The <code class="attribute-name">keyCode</code> for
          <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          or <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a> events is calculated
          as follows:
          </p>

        <ol>
          <li>Read the virtual key code from the operating system's event information, if such information
            is available.</li>
          <li>If an Input Method Editor is processing key input and the event is
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>, return 229.</li>
          <li>If input key when pressed without modifiers would insert a numerical character (0-9),
            return the <abbr title="American Standard Code for Information Interchange">ASCII</abbr> code of that numerical character.</li>
          <li>If input key when pressed without modifiers would insert a lower case character in the
            a-z alphabetical range, return the <abbr title="American Standard Code for Information Interchange">ASCII</abbr> code of the upper case equivalent.</li>
          <li>If the implementation supports a key code conversion table for the operating system and platform,
            look up the value. If the conversion table specifies an alternate virtual key value for the given
            input, return the specified value.</li>
          <li>If the key's function, as determined in an implementation-specific way, corresponds to one of
            the keys in the <a href="#fixed-virtual-key-codes">table of fixed virtual key codes</a>,
            return the corresponding key code.</li>
          <li>Return the virtual key code from the operating system.</li>
          <li>If no key code was found, return 0.</li>
        </ol>
      </section>

      <section property="bibo:hasPart" resource="#determine-keypress-keyCode" typeof="bibo:Chapter" id="determine-keypress-keyCode">
        <h4 resource="#h-determine-keypress-keycode" id="h-determine-keypress-keycode"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.2.2 </span>How to determine <code class="attribute-name">keyCode</code> for <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> events</span></h4>

        <p>The <code class="attribute-name">keyCode</code> for
          <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> events is
          calculated as follows:
          </p>

        <ol>
          <li>If the implementation supports a <em>conflated model</em>, set <code class="attribute-name">keyCode</code>
            to the Unicode code point of the character being entered.</li>
          <li>If the implementation supports a <em>split model</em>, set <code class="attribute-name">keyCode</code> to 0.</li>
        </ol>
      </section>

      <section property="bibo:hasPart" resource="#fixed-virtual-key-codes" typeof="bibo:Chapter" id="fixed-virtual-key-codes">
        <h4 resource="#h-fixed-virtual-key-codes" id="h-fixed-virtual-key-codes"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.2.3 </span>Fixed virtual key codes</span></h4>

        <p>The virtual key codes for the following keys do not usually change with keyboard layouts
          on desktop systems:
          </p>

        <table class="legacy-key-table">
          <tbody><tr>
            <th>Key</th>
            <th class="cell-center">Virtual Key<br>Code</th>
            <th>Notes</th>
          </tr>
          <tr><td><code title="Key Value" class="key">'Backspace'</code></td>   <td class="cell-center">8</td>    <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Tab'</code></td>       <td class="cell-center">9</td>    <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Enter'</code></td>     <td class="cell-center">13</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Shift'</code></td>     <td class="cell-center">16</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Control'</code></td>     <td class="cell-center">17</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Alt'</code></td>       <td class="cell-center">18</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'CapsLock'</code></td>    <td class="cell-center">20</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Escape'</code></td>      <td class="cell-center">27</td>   <td><em>Esc</em></td> </tr>
          <tr><td><code title="Key Value" class="key">' '</code></td>       <td class="cell-center">32</td>   <td><em>Space</em></td> </tr>
          <tr><td><code title="Key Value" class="key">'PageUp'</code></td>      <td class="cell-center">33</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'PageDown'</code></td>    <td class="cell-center">34</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'End'</code></td>       <td class="cell-center">35</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Home'</code></td>      <td class="cell-center">36</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'ArrowLeft'</code></td>   <td class="cell-center">37</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'ArrowUp'</code></td>     <td class="cell-center">38</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'ArrowRight'</code></td>    <td class="cell-center">39</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'ArrowDown'</code></td>   <td class="cell-center">40</td>   <td></td> </tr>
          <tr><td><code title="Key Value" class="key">'Delete'</code></td>      <td class="cell-center">46</td>   <td><em>Del</em></td> </tr>
        </tbody></table>
      </section>

      <section property="bibo:hasPart" resource="#optionally-fixed-virtual-key-codes" typeof="bibo:Chapter" id="optionally-fixed-virtual-key-codes">
        <h4 resource="#h-optionally-fixed-virtual-key-codes" id="h-optionally-fixed-virtual-key-codes"><span property="xhv:role" resource="xhv:heading"><span class="secno">B.2.4 </span>Optionally fixed virtual key codes</span></h4>

        <p>The following punctuation characters <em title="MAY" class="rfc2119">MAY</em> change virtual codes between keyboard layouts, but reporting
          these values will likely be more compatible with legacy content expecting US-English keyboard layout:
          </p>

        <table class="legacy-key-table">
          <tbody><tr>
            <th>Key</th>
            <th class="cell-center">Character</th>
            <th class="cell-center">Virtual Key<br>Code</th>
          </tr>
          <tr><td>Semicolon</td>        <td class="cell-center"><code title="Character Value Glyph" class="glyph">';'</code></td>   <td class="cell-center">186</td>  </tr>
          <tr><td>Colon</td>          <td class="cell-center"><code title="Character Value Glyph" class="glyph">':'</code></td>   <td class="cell-center">186</td>  </tr>
          <tr><td>Equals sign</td>      <td class="cell-center"><code title="Character Value Glyph" class="glyph">'='</code></td>   <td class="cell-center">187</td>  </tr>
          <tr><td>Plus</td>         <td class="cell-center"><code title="Character Value Glyph" class="glyph">'+'</code></td>   <td class="cell-center">187</td>  </tr>
          <tr><td>Comma</td>          <td class="cell-center"><code title="Character Value Glyph" class="glyph">','</code></td>   <td class="cell-center">188</td>  </tr>
          <tr><td>Less than sign</td>     <td class="cell-center"><code title="Character Value Glyph" class="glyph">'&lt;'</code></td>  <td class="cell-center">188</td>  </tr>
          <tr><td>Minus</td>          <td class="cell-center"><code title="Character Value Glyph" class="glyph">'-'</code></td>   <td class="cell-center">189</td>  </tr>
          <tr><td>Underscore</td>       <td class="cell-center"><code title="Character Value Glyph" class="glyph">'_'</code></td>   <td class="cell-center">189</td>  </tr>
          <tr><td>Period</td>         <td class="cell-center"><code title="Character Value Glyph" class="glyph">'.'</code></td>   <td class="cell-center">190</td>  </tr>
          <tr><td>Greater than sign</td>    <td class="cell-center"><code title="Character Value Glyph" class="glyph">'&gt;'</code></td>    <td class="cell-center">190</td>  </tr>
          <tr><td>Forward slash</td>      <td class="cell-center"><code title="Character Value Glyph" class="glyph">'/'</code></td>   <td class="cell-center">191</td>  </tr>
          <tr><td>Question mark</td>      <td class="cell-center"><code title="Character Value Glyph" class="glyph">'?'</code></td>   <td class="cell-center">191</td>  </tr>
          <tr><td>Backtick</td>       <td class="cell-center"><code title="Character Value Glyph" class="glyph">'`'</code></td>   <td class="cell-center">192</td>  </tr>
          <tr><td>Tilde</td>          <td class="cell-center"><code title="Character Value Glyph" class="glyph">'~'</code></td>   <td class="cell-center">192</td>  </tr>
          <tr><td>Opening square bracket</td> <td class="cell-center"><code title="Character Value Glyph" class="glyph">'['</code></td>   <td class="cell-center">219</td>  </tr>
          <tr><td>Opening curly brace</td>  <td class="cell-center"><code title="Character Value Glyph" class="glyph">'{'</code></td>   <td class="cell-center">219</td>  </tr>
          <tr><td>Backslash</td>        <td class="cell-center"><code title="Character Value Glyph" class="glyph">'\'</code></td>   <td class="cell-center">220</td>  </tr>
          <tr><td>Pipe</td>         <td class="cell-center"><code title="Character Value Glyph" class="glyph">'|'</code></td>   <td class="cell-center">220</td>  </tr>
          <tr><td>Closing square bracket</td> <td class="cell-center"><code title="Character Value Glyph" class="glyph">']'</code></td>   <td class="cell-center">221</td>  </tr>
          <tr><td>Closing curly brace</td>  <td class="cell-center"><code title="Character Value Glyph" class="glyph">'}'</code></td>   <td class="cell-center">221</td>  </tr>
          <tr><td>Single quote</td>     <td class="cell-center"><code title="Character Value Glyph" class="glyph">'''</code></td>   <td class="cell-center">222</td>  </tr>
          <tr><td>Double quote</td>     <td class="cell-center"><code title="Character Value Glyph" class="glyph">'"'</code></td>   <td class="cell-center">222</td>  </tr>
        </tbody></table>
      </section>
    </section>
  </section>  <!-- legacy-key-attributes -->

  <!-- Appendix C: Legacy Event Types ========================================================-->
  <section property="bibo:hasPart" resource="#legacy-event-types" typeof="bibo:Chapter" id="legacy-event-types">
    <!--OddPage--><h2 resource="#h-legacy-event-types" id="h-legacy-event-types"><span property="xhv:role" resource="xhv:heading"><span class="secno">C. </span>Legacy Event Types</span></h2>
    <p><em>This section is informative</em></p>

    <p>This section provides a non-normative description of the event types that are deprecated in
      this document.
      </p>

    <p>The purpose of this section is to document the current state of these features and their relation
      to normative events.
      For implementations which do support these events, it is suggested that the definitions provided
      in this section be used.
      </p>

    <p>The following table provides an informative summary of the event types which are deprecated in
      this specification.
      They are included here for reference and completeness.
      </p>

    <table class="data-table">
      <tbody><tr>
        <th>Event Type</th>
        <th>Sync / Async</th>
        <th>Bubbling phase</th>
        <th>Trusted event target types</th>
        <th>DOM interface</th>
        <th>Cancelable</th>
        <th>Default Action</th>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Element</code></td>
        <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
        <td>Yes</td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Element</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMCharacterDataModified"><code>DOMCharacterDataModified</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Text</code>, <code>Comment</code>, <code>ProcessingInstruction</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
        <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMFocusOut"><code>DOMFocusOut</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
        <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMNodeInserted"><code>DOMNodeInserted</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
          <code>ProcessingInstruction</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMNodeInsertedIntoDocument"><code>DOMNodeInsertedIntoDocument</code></a></td>
        <td>Sync</td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
          <code>ProcessingInstruction</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMNodeRemoved"><code>DOMNodeRemoved</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
          <code>ProcessingInstruction</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMNodeRemovedFromDocument"><code>DOMNodeRemovedFromDocument</code></a></td>
        <td>Sync</td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
          <code>ProcessingInstruction</code></td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-DOMSubtreeModified"><code>DOMSubtreeModified</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>DocumentFragment</code>, <code>Element</code>, <code>Attr</code>
        </td>
        <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
        <td><abbr title="Number, Other">No</abbr></td>
        <td>None</td>
      </tr>
      <tr>
        <td><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a></td>
        <td>Sync</td>
        <td>Yes</td>
        <td><code>Element</code></td>
        <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
        <td>Yes</td>
        <td>Varies:
          launch <a class="def" href="#glossary-text-composition-system">text composition system</a>;
          <a class="eventtype" href="#event-type-blur"><code>blur</code></a> and <a class="eventtype" href="#event-type-focus"><code>focus</code></a> events;
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> event;
          other event</td>
      </tr>
    </tbody></table>

    <section property="bibo:hasPart" resource="#legacy-uievent-events" typeof="bibo:Chapter" id="legacy-uievent-events">
      <h3 resource="#h-legacy-uievent-events" id="h-legacy-uievent-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.1 </span>Legacy <a href="#interface-UIEvent"><code>UIEvent</code></a> events</span></h3>

      <!-- DOMActivate -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMActivate"><dfn id="dfn-domactivate"><a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMActivate</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-UIEvent"><code>UIEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element being activated</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>
            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a button, link, or other state-changing element is activated.  Refer to
              <a href="#event-flow-activation">Activation triggers and behavior</a> for more details.</p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class="" id="DOMActivate-deprecated"><strong>Warning!</strong> The <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> <a class="def" href="#glossary-event-type">event type</a> is defined in this specification for reference and completeness, but this specification <a class="def" href="#glossary-deprecated">
              deprecates</a> the use of this event type in favor of the related <a class="def" href="#glossary-event-type">event type</a> <a class="eventtype" href="#event-type-click">
              <code>click</code></a>.  Other specifications <em title="MAY" class="rfc2119">MAY</em> define and maintain their own <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
              <a class="def" href="#glossary-event-type">event type</a> for backwards compatibility.</p></div>

            <div class="note"><div id="h-note69" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="DOMActivate-click"><strong>Note:</strong>   While <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> and <a class="eventtype" href="#event-type-click"><code>click</code></a> are not completely equivalent, implemented behavior for the <a class="eventtype" href="#event-type-click"><code>click</code></a>
              <a class="def" href="#glossary-event-type">event type</a> has developed to encompass the most critical accessibility aspects for which the <a class="eventtype" href="#event-type-DOMActivate">
              <code>DOMActivate</code></a> <a class="def" href="#glossary-event-type">event type</a> was designed, and is more widely implemented.  Content authors are encouraged
              to use the <a class="eventtype" href="#event-type-click"><code>click</code></a> <a class="def" href="#glossary-event-type">event type</a> rather than the related
              <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> or <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a> <a class="def" href="#glossary-event-type">event type</a> to ensure maximum accessibility.</p></div>
          </dd>
        </dl>
      </div>

      <p>Implementations which support the
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
        <a class="def" href="#glossary-event-type">event type</a> <em title="SHOULD" class="rfc2119">SHOULD</em> also dispatch a
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
        event as a <a class="def" href="#glossary-default-action">default action</a> of a
        <a class="eventtype" href="#event-type-click"><code>click</code></a> event which is associated
        with an <a class="def" href="#glossary-activation-trigger">activation trigger</a>.
        However, such implementations <em title="SHOULD" class="rfc2119">SHOULD</em> only initiate the associated
        <a class="def" href="#glossary-activation-behavior">activation behavior</a>
        once for any given occurrence of an
        <a class="def" href="#glossary-activation-trigger">activation trigger</a>.
        </p>

      <div class="example">
        <div class="example-title"></div>
        <p>The <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
          <a class="def" href="#glossary-event-type">event type</a> is <em title="REQUIRED" class="rfc2119">REQUIRED</em> to be supported for
          XForms [<cite><a class="informative" href="#ref-xforms">XFORMS</a></cite>],
          which is intended for implementation within a <a class="def" href="#glossary-host-language">host language</a>.
          In a scenario where a plugin or script-based implementation of XForms is intended for installation
          in a native implementation of this specification which does not support the
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
          <a class="def" href="#glossary-event-type">event type</a>, the XForms
          <a class="def" href="#glossary-user-agent">user agent</a> has to synthesize and dispatch its own
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> events based on
          the appropriate <a class="def" href="#glossary-activation-trigger">activation triggers</a>.
          </p>

        <p>Thus, when a <a class="eventtype" href="#event-type-click"><code>click</code></a> event is dispatched
          by a <a class="def" href="#glossary-user-agent">user agent</a> conforming to UI Events, the
          XForms <a class="def" href="#glossary-user-agent">user agent</a> has to determine whether to synthesize
          a <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> event with the
          same relevant properties as a <a class="def" href="#glossary-default-action">default action</a> of
          that <a class="eventtype" href="#event-type-click"><code>click</code></a> event.
          Appropriate cues might be whether the <a class="eventtype" href="#event-type-click"><code>click</code></a>
          event is <a href="#trusted-events">trusted</a>, or whether its
          <a class="def" href="#glossary-event-target">event target</a> has a
          <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> event listener
          registered.
          </p>
      </div>

      <div class="note"><div id="h-note70" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Authoring Note:</strong>
        Don't rely upon the interoperable support of
        <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
        in many <a class="def" href="#glossary-user-agent">user agents</a>.
        Instead, the <a class="eventtype" href="#event-type-click"><code>click</code></a>
        <a class="def" href="#glossary-event-type">event type</a> should be used since it will provide more
        accessible behavior due to broader implementation support.
        </p></div>

      <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
        The <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a>
        <a class="def" href="#glossary-event-type">event type</a> is deprecated in this specification.
        </p></div>

      <section property="bibo:hasPart" resource="#legacy-uievent-event-order" typeof="bibo:Chapter" id="legacy-uievent-event-order">
        <h4 resource="#h-legacy-uievent-event-order" id="h-legacy-uievent-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.1.1 </span>Activation event order</span></h4>

        <p>If the <code>DOMActivate</code> event is supported by the
          <a class="def" href="#glossary-user-agent">user agent</a>, then the
          events <em title="MUST" class="rfc2119">MUST</em> be dispatched in a set order relative to each other:
          (with only pertinent events listed):
          </p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td></td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a></td>
            <td><a class="def" href="#glossary-default-action">default action</a>, if supported
              by the <a class="def" href="#glossary-user-agent">user agent</a>; synthesized; <code>isTrusted="true"</code>
            </td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td colspan="2">
              <em>All other <a class="def" href="#glossary-default-action">default actions</a>,
              including the <a class="def" href="#glossary-activation-behavior">activation behavior</a></em>
            </td>
          </tr>
        </tbody></table>

        <p>If the focused element is activated by a key event, then the following shows the
          typical sequence of events (with only pertinent events listed):
          </p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
            <td><em title="MUST" class="rfc2119">MUST</em> be a key which can activate the element, such as the
              <code title="Key Value" class="key">'Enter'</code> or <code title="Key Value" class="key">'&nbsp;'</code> key,
              or the element is not activated
            </td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-click"><code>click</code></a></td>
            <td><a class="def" href="#glossary-default-action">default action</a>; synthesized; <code>isTrusted="true"</code></td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a></td>
            <td><a class="def" href="#glossary-default-action">default action</a>, if supported
              by the <a class="def" href="#glossary-user-agent">user agent</a>; synthesized; <code>isTrusted="true"</code>
            </td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td colspan="2">
              <em>All other <a class="def" href="#glossary-default-action">default actions</a>,
              including the <a class="def" href="#glossary-activation-behavior">activation behavior</a></em>
            </td>
          </tr>
        </tbody></table>
      </section>  <!-- legacy-uievent-event-order -->
    </section>  <!-- legacy-uievent-events -->

    <section property="bibo:hasPart" resource="#legacy-focusevent-events" typeof="bibo:Chapter" id="legacy-focusevent-events">
      <h3 resource="#h-legacy-focusevent-events" id="h-legacy-focusevent-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.2 </span>Legacy <a href="#interface-FocusEvent"><code>FocusEvent</code></a> events</span></h3>

      <!-- DOMFocusIn -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMFocusIn"><dfn id="dfn-domfocusin"><a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMFocusIn</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> receiving focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>
            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event
              when an <a class="def" href="#glossary-event-target">event target</a> receives focus.
              The focus <em title="MUST" class="rfc2119">MUST</em> be given to the element before the dispatch of this event type.
              This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the event type
              <a class="eventtype" href="#event-type-focus"><code>focus</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a> event type
              is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type in favor
              of the related event types <a class="eventtype" href="#event-type-focus"><code>focus</code></a>
              and <a class="eventtype" href="#event-type-focusin"><code>focusin</code></a>.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMFocusOut -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMFocusOut"><dfn id="dfn-domfocusout"><a class="eventtype" href="#event-type-DOMFocusOut"><code>DOMFocusOut</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMFocusOut</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-FocusEvent"><code>FocusEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      <a class="def" href="#glossary-event-target">event target</a> losing focus</li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-FocusEvent-relatedTarget"><code class="attribute-name">FocusEvent.relatedTarget</code></a>:
                      <code>null</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>
            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event
              when an <a class="def" href="#glossary-event-target">event target</a> loses focus.
              The focus <em title="MUST" class="rfc2119">MUST</em> be taken from the element before the dispatch of this event type.
              This event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the event type
              <a class="eventtype" href="#event-type-blur"><code>blur</code></a>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMFocusOut"><code>DOMFocusOut</code></a> event
              type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type in
              favor of the related event types <a class="eventtype" href="#event-type-blur"><code>blur</code></a>
              and <a class="eventtype" href="#event-type-focusout"><code>focusout</code></a>.
              </p></div>
          </dd>
        </dl>
      </div>

      <section property="bibo:hasPart" resource="#legacy-focusevent-event-order" typeof="bibo:Chapter" id="legacy-focusevent-event-order">
        <h4 resource="#h-legacy-focusevent-event-order" id="h-legacy-focusevent-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.2.1 </span>Legacy FocusEvent event order</span></h4>

        <p>The following is the typical sequence of events when a focus is shifted between elements,
          including the deprecated
            <a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a>
            and <a class="eventtype" href="#event-type-DOMFocusOut"><code>DOMFocusOut</code></a>
          events. The order shown assumes that no element is initially focused.
          </p>

        <table class="event-sequence-table">
          <tbody><tr>
            <td class="cell-number"></td>
            <td colspan="2"><em>User shifts focus</em></td>
          </tr>
          <tr>
            <td class="cell-number">1.</td>
            <td><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></td>
            <td>Sent before first target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">2.</td>
            <td><a class="eventtype" href="#event-type-focus"><code>focus</code></a></td>
            <td>Sent after first target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">3.</td>
            <td><a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a></td>
            <td>If supported</td>
          </tr>
          <tr>
            <td class="cell-number"></td>
            <td colspan="2"><em>User shifts focus</em></td>
          </tr>
          <tr>
            <td class="cell-number">4.</td>
            <td><a class="eventtype" href="#event-type-focusout"><code>focusout</code></a></td>
            <td>Sent before first target element loses focus</td>
          </tr>
          <tr>
            <td class="cell-number">5.</td>
            <td><a class="eventtype" href="#event-type-focusin"><code>focusin</code></a></td>
            <td>Sent before second target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">6.</td>
            <td><a class="eventtype" href="#event-type-blur"><code>blur</code></a></td>
            <td>Sent after first target element loses focus</td>
          </tr>
          <tr>
            <td class="cell-number">7.</td>
            <td><a class="eventtype" href="#event-type-DOMFocusOut"><code>DOMFocusOut</code></a></td>
            <td>If supported</td>
          </tr>
          <tr>
            <td class="cell-number">8.</td>
            <td><a class="eventtype" href="#event-type-focus"><code>focus</code></a></td>
            <td>Sent after second target element receives focus</td>
          </tr>
          <tr>
            <td class="cell-number">9.</td>
            <td><a class="eventtype" href="#event-type-DOMFocusIn"><code>DOMFocusIn</code></a></td>
            <td>If supported</td>
          </tr>
        </tbody></table>
      </section>  <!-- legacy-focusevent-event-order -->

    </section>  <!-- legacy-focusevent-events -->

    <section property="bibo:hasPart" resource="#legacy-keyboardevent-events" typeof="bibo:Chapter" id="legacy-keyboardevent-events">
      <h3 resource="#h-legacy-keyboardevent-events" id="h-legacy-keyboardevent-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.3 </span>Legacy <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> events</span></h3>

      <p>The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event is the
        traditional method for capturing key events and processing them before the DOM is updated
        with the effects of the key press.
        Code that makes use of the
          <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
        event typically relies on the legacy
          <a href="#widl-KeyboardEvent-charCode">charCode</a>,
          <a href="#widl-KeyboardEvent-keyCode">keyCode</a>,
          and <a href="#widl-KeyboardEvent-which">which</a>
        attributes.
        </p>

      <p>Note that the <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event
        is specific to key events, and has been replaced by the more general event sequence of
        <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
        and <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a> events.
        These new input events are not specific to keyboard actions and can be used to capture
        user input regardless of the original source.
        </p>

      <!-- keypress -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-keypress"><dfn id="dfn-keypress"><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>keypress</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>Varies:
                  launch <a class="def" href="#glossary-text-composition-system">text composition system</a>;
                  <a class="eventtype" href="#event-type-blur"><code>blur</code></a> and <a class="eventtype" href="#event-type-focus"><code>focus</code></a> events;
                  <a class="eventtype" href="#event-type-DOMActivate"><code>DOMActivate</code></a> event;
                  other event</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                        focused element processing the key event or if no element focused, then the
                        <a href="#glossary-body-element">body element</a> if available, otherwise the
                        <a href="#glossary-root-element">root element</a></li>
                    <li><a href="#widl-UIEvent-view"><code class="attribute-name">UIEvent.view</code></a>:
                      <a class="def" href="#glossary-window"><code>Window</code></a></li>
                    <li><a href="#widl-UIEvent-detail"><code class="attribute-name">UIEvent.detail</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-KeyboardEvent-charCode"><code class="attribute-name">KeyboardEvent.charCode</code></a>:
                      legacy character value for this event</li>
                    <li><a href="#widl-KeyboardEvent-keyCode"><code class="attribute-name">KeyboardEvent.keyCode</code></a>:
                      legacy numerical code for this key</li>
                    <li><a href="#widl-KeyboardEvent-which"><code class="attribute-name">KeyboardEvent.which</code></a>:
                      legacy numerical code for this key</li>
                    <li><a href="#widl-KeyboardEvent-key"><code class="attribute-name">KeyboardEvent.key</code></a>:
                      the key value of the key pressed.</li>
                    <li><a href="#widl-KeyboardEvent-code"><code class="attribute-name">KeyboardEvent.code</code></a>:
                      the code value associated with the key's physical placement on the keyboard.</li>
                    <li><a href="#widl-KeyboardEvent-location"><code class="attribute-name">KeyboardEvent.location</code></a>:
                      the location of the key on the device.</li>
                    <li><a href="#widl-KeyboardEvent-altKey"><code class="attribute-name">KeyboardEvent.altKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Alt'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-shiftKey"><code class="attribute-name">KeyboardEvent.shiftKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Shift'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-ctrlKey"><code class="attribute-name">KeyboardEvent.ctrlKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Control'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-metaKey"><code class="attribute-name">KeyboardEvent.metaKey</code></a>:
                      <code>true</code> if <code title="Key Value" class="key">'Meta'</code> modifier was active, otherwise <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-repeat"><code class="attribute-name">KeyboardEvent.repeat</code></a>:
                      <code>false</code></li>
                    <li><a href="#widl-KeyboardEvent-isComposing"><code class="attribute-name">KeyboardEvent.isComposing</code></a>:
                      <code>true</code> if the key event occurs as part of a composition session, otherwise <code>false</code></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>If supported by a <a class="def" href="#glossary-user-agent">user agent</a>, this event <em title="MUST" class="rfc2119">MUST</em>
              be dispatched when a key is pressed down, if and only if that key normally produces a
              <a class="def" href="#glossary-character-value">character value</a>.
              The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event type
              is device dependent and relies on the capabilities of the input devices and how they are
              mapped in the operating system.
              </p>

            <p>This event type <em title="MUST" class="rfc2119">MUST</em> be generated after the <a class="def" href="#glossary-key-mapping">key mapping</a>.
              It <em title="MUST NOT" class="rfc2119">MUST NOT</em> be fired when using an <a class="def" href="#glossary-ime">input method editor</a>.
              </p>

            <p>If this event is canceled, it should prevent the
                <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
              event from firing, in addition to canceling the
                <a class="def" href="#glossary-default-action">default action</a>.
              </p>

            <p>Authors <em title="SHOULD" class="rfc2119">SHOULD</em> use the
                <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
              event instead of the
                <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
              event.
              </p>

            <div class="note"><div id="h-note71" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event is traditionally
              associated with detecting a <a class="def" href="#glossary-character-value">character value</a> rather
              than a physical key, and might not be available on all keys in some configurations.
              </p></div>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><div class="">
              <p><strong>Warning!</strong></p>
              <p>The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event type is defined
                in this specification for reference and completeness, but this specification
                <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
                When in editing contexts, authors can subscribe to the <code>beforeinput</code> event instead.
                </p>
            </div></div>

          </dd>
        </dl>
      </div>

      <section property="bibo:hasPart" resource="#keypress-event-order" typeof="bibo:Chapter" id="keypress-event-order">
        <h4 resource="#h-keypress-event-order" id="h-keypress-event-order"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.3.1 </span><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event order</span></h4>

        <p>The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
          event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the
            <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a>
          event and before the
            <a class="eventtype" href="#event-type-keyup"><code>keyup</code></a>
          event associated with the same key.
          </p>

        <p>The <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
          event type <em title="MUST" class="rfc2119">MUST</em> be dispatched after the
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
          event and before the
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a>
          event associated with the same key.
          </p>

        <p>The sequence of key events for user-agents the support the
          <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a> event
          is demonstrated in the following example:
          </p>

        <div class="example">
          <div class="example-title"></div>
          <table class="event-sequence-table">
            <tbody><tr>
              <td class="cell-number"></td>
              <th>Event Name</th>
              <th class="cell-center"><a href="#widl-KeyboardEvent-key"><code>KeyboardEvent<br>key</code></a></th>
              <th class="cell-center"><a href="http://w3c.github.io/editing-explainer/input-events.html#widl-InputEvent-data"><code>InputEvent<br>data</code></a></th>
            </tr>
            <tr>
              <td class="cell-number">1.</td>
              <td><a class="eventtype" href="#event-type-keydown"><code>keydown</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'a'</code></td>
              <td class="cell-center"></td>
            </tr>
            <tr>
              <td class="cell-number">2.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"><code title="Key Value" class="key">'a'</code></td>
            </tr>
            <tr>
              <td class="cell-number">3.</td>
              <td><a class="eventtype" href="#event-type-keypress"><code>keypress</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'a'</code></td>
              <td class="cell-center"></td>
            </tr>
            <tr>
              <td class="cell-number"></td>
              <td colspan="3"><em>Any <a class="def" href="#glossary-default-action">default actions</a> related to this key, such as inserting a
                character in to the DOM.</em>
              </td>
              <td></td>
            </tr>
            <tr>
              <td class="cell-number">4.</td>
              <td><a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a></td>
              <td class="cell-center"></td>
              <td class="cell-center"></td>
            </tr>
            <tr>
              <td class="cell-number">5.</td>
              <td><a class="eventtype" href="#event-type-keyup"><code>keyup</code></a></td>
              <td class="cell-center"><code title="Key Value" class="key">'a'</code></td>
              <td class="cell-center"></td>
            </tr>
          </tbody></table>
        </div>
      </section>  <!-- keypress-event-order -->
    </section>  <!-- legacy-keyboardevent-events -->

    <section property="bibo:hasPart" resource="#legacy-mutationevent-events" typeof="bibo:Chapter" id="legacy-mutationevent-events">
      <h3 resource="#h-legacy-mutationevent-events" id="h-legacy-mutationevent-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.4 </span>Legacy <a href="#interface-MutationEvent"><code>MutationEvent</code></a> events</span></h3>

      <p>The mutation and mutation name event modules are designed to allow notification of any
        changes to the structure of a document, including attribute, text, or name modifications.
        </p>

      <div class="note"><div id="h-note72" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
        None of the event types associated with the <code>MutationEvent</code> interface are
        designated as cancelable.
        This stems from the fact that it is very difficult to make use of existing DOM interfaces
        which cause document modifications if any change to the document might or might not take
        place due to cancelation of the resulting event.
        Although this is still a desired capability, it was decided that it would be better left
        until the addition of transactions into the DOM.
        </p></div>

      <p>Many single modifications of the tree can cause multiple mutation events to be dispatched.
        Rather than attempt to specify the ordering of mutation events due to every possible
        modification of the tree, the ordering of these events is left to the implementation.
        </p>

      <div class="warning"><div class="warning-title"><span>Warning</span></div><div class="">
        <p><strong>Warning!</strong></p>
        <p>The <a href="#interface-MutationEvent">MutationEvent interface</a> was introduced in
          DOM Level 2 Events, but has not yet been completely and interoperably implemented across
          <a class="def" href="#glossary-user-agent">user agents</a>.
          In addition, there have been critiques that the interface, as designed, introduces a
          performance and implementation challenge.
          </p>
        <p>DOM4 [<a href="#references-DOM4">DOM4</a>] provides a new mechanism using a
          <code>MutationObserver</code> interface which addresses the use cases that mutation events
          solve, but in a more performant manner.
          Thus, this specification describes mutation events for reference and completeness of legacy
          behavior, but <a class="def" href="#glossary-deprecated">deprecates</a> the use of the
          <a href="#interface-MutationEvent"><code>MutationEvent</code></a> interface.
          </p>
      </div></div>

      <section property="bibo:hasPart" resource="#interface-MutationEvent" typeof="bibo:Chapter" id="interface-MutationEvent">
        <h4 resource="#h-interface-mutationevent" id="h-interface-mutationevent"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.4.1 </span>Interface MutationEvent</span></h4>

        <p class="intro-dom">Introduced in DOM Level 2, deprecated in this specification</p>

        <p>The <code>MutationEvent</code> interface provides specific contextual information associated
          with Mutation events.
          </p>

        <p>To create an instance of the <code>MutationEvent</code> interface, use the
          <a href="#widl-DocumentEvent-createEvent"><code>DocumentEvent.createEvent("MutationEvent")</code></a>
          method call.
          </p>

        <pre class="idl"><span class="idlInterface" id="idl-def-MutationEvent">interface <span class="idlInterfaceID">MutationEvent</span> : <span class="idlSuperclass"><a class="internalDFN" href="#dfn-event">Event</a></span> {
<span class="idlSectionComment">    // attrChangeType</span>
<span class="idlConst">    const <span class="idlConstType">unsigned short</span> <span class="idlConstName"><a href="#widl-MutationEvent-MODIFICATION">MODIFICATION</a></span> = <span class="idlConstValue">1</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned short</span> <span class="idlConstName"><a href="#widl-MutationEvent-ADDITION">ADDITION</a></span> = <span class="idlConstValue">2</span>;</span>
<span class="idlConst">    const <span class="idlConstType">unsigned short</span> <span class="idlConstName"><a href="#widl-MutationEvent-REMOVAL">REMOVAL</a></span> = <span class="idlConstValue">3</span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">Node?</span>          <span class="idlAttrName"><a href="#widl-MutationEvent-relatedNode">relatedNode</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span>      <span class="idlAttrName"><a href="#widl-MutationEvent-prevValue">prevValue</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span>      <span class="idlAttrName"><a href="#widl-MutationEvent-newValue">newValue</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">DOMString</span>      <span class="idlAttrName"><a href="#widl-MutationEvent-attrName">attrName</a></span>;</span>
<span class="idlAttribute">    readonly    attribute <span class="idlAttrType">unsigned short</span> <span class="idlAttrName"><a href="#widl-MutationEvent-attrChange">attrChange</a></span>;</span>
<span class="idlMethod">    <span class="idlMethType">void</span> <span class="idlMethName"><a href="#widl-MutationEvent-initMutationEvent">initMutationEvent</a></span> (<span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">typeArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">bubblesArg</span></span>, <span class="idlParam"><span class="idlParamType">boolean</span> <span class="idlParamName">cancelableArg</span></span>, <span class="idlParam"><span class="idlParamType">Node?</span> <span class="idlParamName">relatedNodeArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">prevValueArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">newValueArg</span></span>, <span class="idlParam"><span class="idlParamType">DOMString</span> <span class="idlParamName">attrNameArg</span></span>, <span class="idlParam"><span class="idlParamType">unsigned short</span> <span class="idlParamName">attrChangeArg</span></span>);</span>
};</span></pre><section property="bibo:hasPart" resource="#attributes-6" typeof="bibo:Chapter" id="attributes-6"><h5 resource="#h-attributes-6" id="h-attributes-6"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.4.1.1 </span>Attributes</span></h5><dl class="attributes"><dt id="widl-MutationEvent-attrChange"><code>attrChange</code> of type <span class="idlAttrType">unsigned short</span>, readonly   </dt><dd>
            <p><code>attrChange</code> indicates the type of change which triggered the
              <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event. The values can be <code>MODIFICATION</code>, <code>ADDITION</code>,
              or <code>REMOVAL</code>.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>0</code>.
              </p>

            <div class="note"><div id="h-note73" role="heading" aria-level="6" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              There is no defined constant for the attrChange value of 0 (the un-initialized value).
              </p></div>
          </dd><dt id="widl-MutationEvent-attrName"><code>attrName</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>attrName</code> indicates the name of the changed <code>Attr</code> node in
              a <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).
              </p>
          </dd><dt id="widl-MutationEvent-newValue"><code>newValue</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>newValue</code> indicates the new value of the <code>Attr</code> node in
              <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              events, and of the <code>CharacterData</code> node in
              <a class="eventtype" href="#event-type-DOMCharacterDataModified"><code>DOMCharacterDataModified</code></a>
              events.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).
              </p>
          </dd><dt id="widl-MutationEvent-prevValue"><code>prevValue</code> of type <span class="idlAttrType">DOMString</span>, readonly   </dt><dd>
            <p><code>prevValue</code> indicates the previous value of the <code>Attr</code> node
              in <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              events, and of the <code>CharacterData</code> node in
              <a class="eventtype" href="#event-type-DOMCharacterDataModified"><code>DOMCharacterDataModified</code></a>
              events.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of this
              attribute <em title="MUST" class="rfc2119">MUST</em> be <code>""</code> (the empty string).
              </p>
          </dd><dt id="widl-MutationEvent-relatedNode"><code>relatedNode</code> of type <span class="idlAttrType">Node</span>, readonly   , nullable</dt><dd>
            <p><code>relatedNode</code> <em title="MUST" class="rfc2119">MUST</em> be used to identify a secondary node related to a
              mutation event.
              For example, if a mutation event is dispatched to a node indicating that its parent
              has changed, the <code>relatedNode</code> will be the changed parent.
              If an event is instead dispatched to a subtree indicating a node was changed
              within it, the <code>relatedNode</code> <em title="MUST" class="rfc2119">MUST</em> be the changed node.
              In the case of the
              <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event, it indicates the <code>Attr</code> node which was modified, added, or removed.
              </p>

            <p>The <a class="def" href="#glossary-un-initialized-value">un-initialized value</a> of
              this attribute <em title="MUST" class="rfc2119">MUST</em> be <code>null</code>.
              </p>
          </dd></dl></section><section property="bibo:hasPart" resource="#methods-9" typeof="bibo:Chapter" id="methods-9"><h5 resource="#h-methods-9" id="h-methods-9"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.4.1.2 </span>Methods</span></h5><dl class="methods"><dt id="widl-MutationEvent-initMutationEvent"><code>initMutationEvent</code></dt><dd>
            <p>Initializes attributes of a <code>MutationEvent</code> object.
              This method has the same behavior as <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a>.
              </p>


          <table class="parameters"><tbody><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">typeArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">bubblesArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">cancelableArg</td><td class="prmType"><code>boolean</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Refer to the <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a> method for a description of this parameter.</p>
              </td></tr><tr><td class="prmName">relatedNodeArg</td><td class="prmType"><code>Node</code></td><td class="prmNullTrue"><span role="img" aria-label="True">✔</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MutationEvent-relatedNode"><code>MutationEvent.relatedNode</code></a>.</p>
              </td></tr><tr><td class="prmName">prevValueArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MutationEvent-prevValue"><code>MutationEvent.prevValue</code></a>.
                  This value <em title="MAY" class="rfc2119">MAY</em> be the <a class="def" href="#glossary-empty-string">empty string</a>.
                  </p>
              </td></tr><tr><td class="prmName">newValueArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MutationEvent-newValue"><code>MutationEvent.newValue</code></a>.
                  This value <em title="MAY" class="rfc2119">MAY</em> be the <a class="def" href="#glossary-empty-string">empty string</a>.
                  </p>
              </td></tr><tr><td class="prmName">attrNameArg</td><td class="prmType"><code>DOMString</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MutationEvent-attrName"><code>MutationEvent.attrName</code></a>.
                  This value <em title="MAY" class="rfc2119">MAY</em> be the <a class="def" href="#glossary-empty-string">empty string</a>.
                  </p>
              </td></tr><tr><td class="prmName">attrChangeArg</td><td class="prmType"><code>unsigned short</code></td><td class="prmNullFalse"><span role="img" aria-label="False">✘</span></td><td class="prmOptFalse"><span role="img" aria-label="False">✘</span></td><td class="prmDesc">
                <p>Specifies <a href="#widl-MutationEvent-attrChange"><code>MutationEvent.attrChange</code></a>.
                  This value <em title="MAY" class="rfc2119">MAY</em> be <code>0</code>.
                  </p>
              </td></tr></tbody></table><div><em>Return type: </em><code>void</code></div></dd></dl></section><section property="bibo:hasPart" resource="#constants-2" typeof="bibo:Chapter" id="constants-2"><h5 resource="#h-constants-2" id="h-constants-2"><span property="xhv:role" resource="xhv:heading"><span class="secno">C.4.1.3 </span>Constants</span></h5><dl class="constants"><dt id="widl-MutationEvent-ADDITION"><code>ADDITION</code> of type <span class="idlConstType">unsigned short</span></dt><dd>
            <p>The <code>Attr</code> was just added.</p>
          </dd><dt id="widl-MutationEvent-MODIFICATION"><code>MODIFICATION</code> of type <span class="idlConstType">unsigned short</span></dt><dd>
            <p>The <code>Attr</code> was modified in place.</p>
          </dd><dt id="widl-MutationEvent-REMOVAL"><code>REMOVAL</code> of type <span class="idlConstType">unsigned short</span></dt><dd>
            <p>The <code>Attr</code> was just removed.</p>
          </dd></dl></section>
      </section>

      <p>The mutation event types are listed below.</p>

      <!-- DOMAttrModified -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMAttrModified"><dfn id="dfn-domattrmodified"><a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMAttrModified</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element whose attribute is being modified</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the name of the changed <code>Attr</code> node</li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      the numerical code corresponding to the most applicable <a href="#idl-def-MutationEvent">attrChangeType</a></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      the <code>Attr</code> node that has been modified, added, or removed.</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      new value of the attribute, if the <code>Attr</code> node has been added or modified</li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      previous value of the attribute, if the <code>Attr</code> node has been removed or modified</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event after
              an <code>Attr.value</code> has been modified and after an <code>Attr</code> node has been
              added to or removed from an <code>Element</code>.
              The <a class="def" href="#glossary-event-target">event target</a> of this event <em title="MUST" class="rfc2119">MUST</em> be
              the <code>Element</code> node where the change occurred.
              It is implementation dependent whether this event type occurs when the children of the
              <code>Attr</code> node are changed in ways that do not affect the value of <code>Attr.value</code>.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event type is defined in this specification for reference and completeness, but this
              specification <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMCharacterDataModified -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMCharacterDataModified"><dfn id="dfn-domcharacterdatamodified"><a class="eventtype" href="#event-type-DOMCharacterDataModified"><code>DOMCharacterDataModified</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMCharacterDataModified</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Text</code>, <code>Comment</code>, <code>ProcessingInstruction</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      object whose content is being modified</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      parent node of the object whose content is being modified</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      new value of the object</li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      previous value of the object</li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event
              after <code>CharacterData.data</code> or <code>ProcessingInstruction.data</code>
              have been modified, but the node itself has not been inserted or deleted.
              The <a class="def" href="#glossary-event-target">event target</a> of this event <em title="MUST" class="rfc2119">MUST</em>
              be the <code>CharacterData</code> node or the <code>ProcessingInstruction</code> node.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMCharacterDataModified"><code>DOMCharacterDataModified</code></a>
              event type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMNodeInserted -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMNodeInserted"><dfn id="dfn-domnodeinserted"><a class="eventtype" href="#event-type-DOMNodeInserted"><code>DOMNodeInserted</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMNodeInserted</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
                  <code>ProcessingInstruction</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element which is being inserted</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      parent node of the node that has been inserted, or the <code>ownerElement</code> in the case of <code>Attr</code> nodes</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event type when
              a node other than an <code>Attr</code> node has been added as a child of another node.
              A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MAY" class="rfc2119">MAY</em> dispatch this event when
              an <code>Attr</code> node has been added to an <code>Element</code> node
              (see <a href="#DOMNodeInserted-attr">note</a> below).
              This event <em title="MUST" class="rfc2119">MUST</em> be dispatched after the insertion has taken place.
              The <a class="def" href="#glossary-event-target">event target</a> of this event <em title="MUST" class="rfc2119">MUST</em> be the
              node being inserted.
              </p>

            <div class="note"><div id="h-note74" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="DOMNodeInserted-attr"><strong>Note:</strong>
              For detecting attribute insertion, use the
                <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event type instead.
              </p></div>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMNodeInserted"><code>DOMNodeInserted</code></a> event
              type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMNodeInsertedIntoDocument -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMNodeInsertedIntoDocument"><dfn id="dfn-domnodeinsertedintodocument"><a class="eventtype" href="#event-type-DOMNodeInsertedIntoDocument"><code>DOMNodeInsertedIntoDocument</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMNodeInsertedIntoDocument</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
                  <code>ProcessingInstruction</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element which is being inserted</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      parent node of the node that has been inserted, or the <code>ownerElement</code> in the case of <code>Attr</code> nodes</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a node
              has been inserted into a document, either through direct insertion of the node or insertion of a
              subtree in which it is contained.
              A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MAY" class="rfc2119">MAY</em>  treat an <code>Attr</code>
              node as part of an <code>Element</code>'s subtree.
              This event <em title="MUST" class="rfc2119">MUST</em> be dispatched after the insertion has taken place.
              The <a class="def" href="#glossary-event-target">event target</a> of this event <em title="MUST" class="rfc2119">MUST</em> be the node
              being inserted.
              If the node is being directly inserted, the event type
                <a class="eventtype" href="#event-type-DOMNodeInserted"><code>DOMNodeInserted</code></a>
              <em title="MUST" class="rfc2119">MUST</em> occur before this event type.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMNodeInsertedIntoDocument"><code>DOMNodeInsertedIntoDocument</code></a>
              event type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMNodeRemoved -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMNodeRemoved"><dfn id="dfn-domnoderemoved"><a class="eventtype" href="#event-type-DOMNodeRemoved"><code>DOMNodeRemoved</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMNodeRemoved</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
                  <code>ProcessingInstruction</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element which is being removed</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      the parent node of the node being removed, or the <code>ownerElement</code> in the case of <code>Attr</code> nodes</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a node
              other than an <code>Attr</code> node is being removed from its parent node.
              A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MAY" class="rfc2119">MAY</em> dispatch this event when an
              <code>Attr</code> node is being removed from its <code>ownerElement</code>
              (see <a href="#DOMNodeRemoved-attr">note</a> below).
              This event <em title="MUST" class="rfc2119">MUST</em> be dispatched before the removal takes place. The
              <a class="def" href="#glossary-event-target">event target</a> of this event <em title="MUST" class="rfc2119">MUST</em> be the node being removed.
              </p>

            <div class="note"><div id="h-note75" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class="" id="DOMNodeRemoved-attr"><strong>Note:</strong>
              For reliably detecting attribute removal, use the
                <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event type instead.
              </p></div>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMNodeRemoved"><code>DOMNodeRemoved</code></a> event type
              is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMNodeRemovedFromDocument -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMNodeRemovedFromDocument"><dfn id="dfn-domnoderemovedfromdocument"><a class="eventtype" href="#event-type-DOMNodeRemovedFromDocument"><code>DOMNodeRemovedFromDocument</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMNodeRemovedFromDocument</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><code>Element</code>, <code>Attr</code>, <code>Text</code>, <code>Comment</code>, <code>DocumentType</code>,
                  <code>ProcessingInstruction</code></td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      element which is being removed</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      the parent node of the node being removed, or the <code>ownerElement</code> in the case of <code>Attr</code> nodes</li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MUST" class="rfc2119">MUST</em> dispatch this event when a node is
              being removed from a document, either through direct removal of the node or removal of a subtree in
              which it is contained.
              A <a class="def" href="#glossary-user-agent">user agent</a> <em title="MAY" class="rfc2119">MAY</em> treat an <code>Attr</code>
              node as part of an <code>Element</code>'s subtree.
              This event <em title="MUST" class="rfc2119">MUST</em> be dispatched before the removal takes place.
              The <a class="def" href="#glossary-event-target">event target</a> of this event type <em title="MUST" class="rfc2119">MUST</em> be the node
              being removed.
              If the node is being directly removed, the event type
                <a class="eventtype" href="#event-type-DOMNodeRemoved"><code>DOMNodeRemoved</code></a>
              <em title="MUST" class="rfc2119">MUST</em> occur before this event type.
              </p>

            <div class="note"><div id="h-note76" role="heading" aria-level="4" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong>
              For reliably detecting attribute removal, use the
                <a class="eventtype" href="#event-type-DOMAttrModified"><code>DOMAttrModified</code></a>
              event type instead.
              </p></div>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMNodeRemovedFromDocument"><code>DOMNodeRemovedFromDocument</code></a>
              event type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

      <!-- DOMSubtreeModified -->
      <div class="event-definition">
        <dl>
          <dt id="event-type-DOMSubtreeModified"><dfn id="dfn-domsubtreemodified"><a class="eventtype" href="#event-type-DOMSubtreeModified"><code>DOMSubtreeModified</code></a></dfn></dt>
          <dd>
            <table class='old_css_table'>
              <tbody><tr>
                <th>Type</th>
                <td><strong><code>DOMSubtreeModified</code></strong></td>
              </tr>
              <tr>
                <th>Interface</th>
                <td><a href="#interface-MutationEvent"><code>MutationEvent</code></a></td>
              </tr>
              <tr>
                <th>Sync / Async</th>
                <td>Sync</td>
              </tr>
              <tr>
                <th>Bubbles</th>
                <td>Yes</td>
              </tr>
              <tr>
                <th>Trusted Targets</th>
                <td><a class="def" href="#glossary-window"><code>Window</code></a>, <code>Document</code>, <code>DocumentFragment</code>, <code>Element</code>, <code>Attr</code>
                </td>
              </tr>
              <tr>
                <th>Cancelable</th>
                <td><abbr title="Number, Other">No</abbr></td>
              </tr>
              <tr>
                <th>Default action</th>
                <td>None</td>
              </tr>
              <tr>
                <th>Context<br>(trusted events)</th>
                <td>
                  <ul>
                    <li><a href="#widl-Event-target"><code class="attribute-name">Event.target</code></a>:
                      parent node of subtree being modified</li>
                    <li><a href="#widl-MutationEvent-attrName"><code class="attribute-name">MutationEvent.attrName</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-attrChange"><code class="attribute-name">MutationEvent.attrChange</code></a>:
                      <code>0</code></li>
                    <li><a href="#widl-MutationEvent-relatedNode"><code class="attribute-name">MutationEvent.relatedNode</code></a>:
                      <code>null</code></li>
                    <li><a href="#widl-MutationEvent-newValue"><code class="attribute-name">MutationEvent.newValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                    <li><a href="#widl-MutationEvent-prevValue"><code class="attribute-name">MutationEvent.prevValue</code></a>:
                      the <a class="def" href="#glossary-empty-string">empty string</a></li>
                  </ul>
                </td>
              </tr>
            </tbody></table>

            <p>This is a general event for notification of all changes to the document.
              It can be used instead of the more specific mutation and mutation name events.
              It <em title="MAY" class="rfc2119">MAY</em> be dispatched after a single modification to the document or, at the implementation's
              discretion, after multiple changes have occurred.
              The latter case <em title="SHOULD" class="rfc2119">SHOULD</em> generally be used to accommodate multiple changes which occur either
              simultaneously or in rapid succession.
              The target of this event <em title="MUST" class="rfc2119">MUST</em> be the lowest common parent of the changes which have taken place.
              This event <em title="MUST" class="rfc2119">MUST</em> be dispatched after any other events caused by the mutation(s) have occurred.
              </p>

            <div class="warning"><div class="warning-title"><span>Warning</span></div><p class=""><strong>Warning!</strong>
              The <a class="eventtype" href="#event-type-DOMSubtreeModified"><code>DOMSubtreeModified</code></a> event
              type is defined in this specification for reference and completeness, but this specification
              <a class="def" href="#glossary-deprecated">deprecates</a> the use of this event type.
              </p></div>
          </dd>
        </dl>
      </div>

    </section>  <!-- legacy-mutationevent-events -->

  </section>  <!-- legacy-event-types -->

  <!-- Appendix D: Extending Events ========================================================-->
  <section property="bibo:hasPart" resource="#extending-events" typeof="bibo:Chapter" id="extending-events">
    <!--OddPage--><h2 resource="#h-extending-events" id="h-extending-events"><span property="xhv:role" resource="xhv:heading"><span class="secno">D. </span>Extending Events</span></h2>
    <p><em>This section is informative</em></p>

    <section property="bibo:hasPart" resource="#extending-events-intro" typeof="bibo:Chapter" id="extending-events-intro">
      <h3 resource="#h-extending-events-intro" id="h-extending-events-intro"><span property="xhv:role" resource="xhv:heading"><span class="secno">D.1 </span>Introduction</span></h3>

      <p>This specification defines several interfaces and many events, however, this is not
        an exhaustive set of events for all purposes.
        To allow content authors and implementers to add desired functionality, this specification
        provides two mechanisms for extend this set of interfaces and events without creating conflicts:
          <a href="#extending-events-Custom_Events">custom events</a>
        and <a href="#extending-events-Impl_Extensions">implementation-specific extensions</a>.
        </p>
    </section>  <!-- extending-events-intro -->

    <section property="bibo:hasPart" resource="#extending-events-Custom_Events" typeof="bibo:Chapter" id="extending-events-Custom_Events">
      <h3 resource="#h-extending-events-custom_events" id="h-extending-events-custom_events"><span property="xhv:role" resource="xhv:heading"><span class="secno">D.2 </span>Custom Events</span></h3>

      <p>A script author <em title="MAY" class="rfc2119">MAY</em> wish to define an application in terms of functional components, with event
        types that are meaningful to the application architecture.
        The content author can use the <a href="#interface-CustomEvent"><code>CustomEvent</code></a> interface
        to create their own events appropriate to the level of abstraction they are using.
        </p>

      <div class="example">
        <div class="example-title"></div>
        <p>A content author might have created an application which features a dynamically generated bar chart.
          This bar chart is meant to be updated every 5 minutes, or when a feed shows new information, or
          when the user refreshes it manually by clicking a button.
          There are several handlers that have to be called when the chart needs to be updated:
          the application has to fetch the most recent data, show an icon to the user that the event is being
          updated, and rebuild the chart.
          To manage this, the content author can choose to create a custom <q>updateChart</q> event,
          which is fired whenever one of the trigger conditions is met:
          </p>
<pre><code>
var chartData = ...;
var evt = document.createEvent("CustomEvent");
evt.initCustomEvent( "updateChart", true, false, { data: chartData });
document.documentElement.dispatchEvent(evt);
</code></pre>
      </div>
    </section>  <!-- extending-events-Custom_Events -->

    <section property="bibo:hasPart" resource="#extending-events-Impl_Extensions" typeof="bibo:Chapter" id="extending-events-Impl_Extensions">
      <h3 resource="#h-extending-events-impl_extensions" id="h-extending-events-impl_extensions"><span property="xhv:role" resource="xhv:heading"><span class="secno">D.3 </span>Implementation-Specific Extensions</span></h3>

      <p>While a new event is being designed and prototyped, or when an event is intended for implementation-specific
        functionality, it is desirable to distinguish it from standardized events.
        Implementors <em title="SHOULD" class="rfc2119">SHOULD</em> prefix event types specific to their implementations with a short string to distinguish
        it from the same event in other implementations and from standardized events.
        This is similar to the
          <a href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords" title="CSS 2.1: Syntax and basic data types">vendor-specific keyword prefixes</a>
        in CSS, though without the dashes (<code>"-"</code>) used in CSS, since that can cause problems when used
        as an attribute name in Javascript.
        </p>

      <div class="example">
        <div class="example-title"></div>
        <p>A particular browser vendor, <q>FooCorp</q>, might wish to introduce a new event, <code class="eventtype">jump</code>.
          This vendor implements <code class="eventtype">fooJump</code> in their browser, using their
          vendor-specific prefix: <code>'foo'</code>.
          Early adopters start experimenting with the event, using
            <code>someElement.addEventListener("fooJump", doJump, false )</code>,
          and provide feedback to FooCorp, who change the behavior of <code class="eventtype">fooJump</code> accordingly.
          </p>

        <p>After some time, another vendor, <q>BarOrg</q>, decides they also want the functionality, but implement
          it slightly differently, so they use their own vendor-specific prefix, <code>"bar"</code> in their
          event type name: <code class="eventtype">barJump</code>.
          Content authors experimenting with this version of the <code class="eventtype">jump</code> event type
          register events with BarOrg's event type name.
          Content authors who wish to write code that accounts for both browsers can either register each event type
          separately with specific handlers, or use the same handler and switch on the name of the event type.
          Thus, early experiments in different codebases do not conflict, and the early adopter is able to write
          easily-maintained code for multiple implementations.
          </p>

        <p>Eventually, as the feature matures, the behavior of both browsers stabilizes and might converge due to
          content author and user feedback or through formal standardization.
          As this stabilization occurs, and risk of conflicts decrease, content authors can remove the forked code,
          and use the <code class="eventtype">jump</code> event type name (even before it is formally standardized)
          using the same event handler and the more generic registration method
            <code>someElement.addEventListener( "jump", doJump, false)</code>.
          </p>
      </div>

      <section property="bibo:hasPart" resource="#extending-events-prefixes" typeof="bibo:Chapter" id="extending-events-prefixes">
        <h4 resource="#h-extending-events-prefixes" id="h-extending-events-prefixes"><span property="xhv:role" resource="xhv:heading"><span class="secno">D.3.1 </span>Known Implementation-Specific Prefixes</span></h4>

        <p>At the time of writing, the following event-type name prefixes are known to exist:
          </p>

        <table>
          <thead>
            <tr>
              <th>Prefix</th>
              <th>Web Engine (Organization)</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td><code>moz</code>, <code>Moz</code></td>
              <td>Gecko (Mozilla)</td>
            </tr>
            <tr>
              <td><code>ms</code>, <code>MS</code></td>
              <td>Trident (Microsoft)</td>
            </tr>
            <tr>
              <td><code>o</code>, <code>O</code></td>
              <td>Presto (Opera Software)</td>
            </tr>
            <tr>
              <td><code>webkit</code></td>
              <td>WebKit (Apple, Google, others)</td>
            </tr>
          </tbody>
        </table>
      </section>  <!-- extending-events-prefixes -->
    </section>  <!-- extending-events-Impl_Extensions -->
  </section>  <!-- extending-events -->

  <!-- Appendix E: Security Considerations ========================================================-->
  <section property="bibo:hasPart" resource="#security-considerations" typeof="bibo:Chapter" id="security-considerations">
    <!--OddPage--><h2 resource="#h-security-considerations" id="h-security-considerations"><span property="xhv:role" resource="xhv:heading"><span class="secno">E. </span>Security Considerations</span></h2>

    <p>This appendix discusses security considerations for UI Events implementations.
      The discussion is limited to security issues that arise directly from implementation of the event
      model, APIs and events defined in this specification.
      Implementations typically support other features like scripting languages, other APIs and
      additional events not defined in this document.
      These features constitute an unknown factor and are out of scope of this document.
      Implementers <em title="SHOULD" class="rfc2119">SHOULD</em> consult the specifications of such features for their respective
      security considerations.
      </p>

    <p>Many of the event types defined in this specification are dispatched in response to user actions.
      This allows malicious event listeners to gain access to information users would typically consider
      confidential, e.g., typos they might have made when filling out a form, if they reconsider their
      answer to a multiple choice question shortly before submitting a form, their typing rate or primary
      input mechanism.
      In the worst case, malicious event listeners could capture all user interactions and submit them
      to a third party through means (not defined in this specification) that are generally available
      in DOM implementations, such as the XMLHttpRequest interface.
      </p>

    <p>In DOM implementations that support facilities to load external data, events like the
      <a href="#dfn-error" class="eventtype internalDFN"><code>error</code></a> event can provide access to sensitive information about
      the environment of the computer system or network.
      An example would be a malicious HTML document that attempts to embed a resource on the local network
      or the localhost on different ports.
      An embedded <a class="def" href="#glossary-DOM-application">DOM application</a> could then listen
      for <a href="#dfn-error" class="eventtype internalDFN"><code>error</code></a> and <a href="#dfn-load" class="eventtype internalDFN"><code>load</code></a> events
      to determine which other computers in a network are accessible from the local system or which ports
      are open on the system to prepare further attacks.
      </p>

    <p>An implementation of UI Events alone is generally insufficient to perform attacks of this kind
      and the security considerations of the facilities that possibly support such attacks apply.
      For conformance with this specification, DOM implementations <em title="MAY" class="rfc2119">MAY</em> take reasonable steps to ensure that
      <a class="def" href="#glossary-DOM-application">DOM applications</a> do not get access to confidential
      or sensitive information.
      For example, they might choose not to dispatch <a href="#dfn-load" class="eventtype internalDFN"><code>load</code></a> events to
      nodes that attempt to embed resources on the local network.
      </p>

  </section>  <!-- security-considerations -->

  <!-- Appendix F: Changes ========================================================-->
  <section property="bibo:hasPart" resource="#changes-from-earlier-versions" typeof="bibo:Chapter" id="changes-from-earlier-versions">
    <!--OddPage--><h2 resource="#h-changes-from-earlier-versions" id="h-changes-from-earlier-versions"><span property="xhv:role" resource="xhv:heading"><span class="secno">F. </span>Changes</span></h2>

    <section property="bibo:hasPart" resource="#changes-DOMEvents2to3Changes" typeof="bibo:Chapter" id="changes-DOMEvents2to3Changes">
      <h3 resource="#h-changes-domevents2to3changes" id="h-changes-domevents2to3changes"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1 </span>Changes between DOM Level 2 Events and UI Events (formerly DOM Level 3 Events)</span></h3>

      <p>Numerous clarifications to the interfaces and event types have been made.
        The <code>HTMLEvents</code> module is no longer defined in this document.
        The <a href="#dfn-focus" class="eventtype internalDFN"><code>focus</code></a> and <a href="#dfn-blur" class="eventtype internalDFN"><code>blur</code></a>
        events have been added to the <a href="#interface-UIEvent"><code>UIEvent</code></a>
        module, and the <a href="#dfn-dblclick" class="eventtype internalDFN"><code>dblclick</code></a> event has been added to the
        <a href="#interface-MouseEvent"><code>MouseEvent</code></a> module.
        This new specification provides a better separation between the DOM event flow,
        the event types, and the DOM interfaces.
        </p>

      <section property="bibo:hasPart" resource="#changes-DOMEvents2to3Changes-flow" typeof="bibo:Chapter" id="changes-DOMEvents2to3Changes-flow">
        <h4 resource="#h-changes-domevents2to3changes-flow" id="h-changes-domevents2to3changes-flow"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1.1 </span>Changes to DOM Level 2 event flow</span></h4>

        <p>This new specification introduced the following new concepts in the event flow:
          </p>

        <ul>
          <li>Event listeners are now ordered. In DOM Level 2, the event ordering was unspecified.</li>
          <li>The event flow now includes the <a class="def" href="#glossary-window"><code>Window</code></a>, to
            reflect existing implementations.</li>
        </ul>
      </section>

      <section property="bibo:hasPart" resource="#changes-DOMEvents2to3Changes-event-types" typeof="bibo:Chapter" id="changes-DOMEvents2to3Changes-event-types">
        <h4 resource="#h-changes-domevents2to3changes-event-types" id="h-changes-domevents2to3changes-event-types"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1.2 </span>Changes to DOM Level 2 event types</span></h4>

        <p>Many clarifications have been made on the event types.
          The conformance is now explicitly defined against the event types, and not only in terms
          of interfaces used by the event types.
          </p>

        <p><code>"MutationEvents"</code> have been deprecated.
          Support for namespaced events, present in early drafts of this specification, has also been removed.
          </p>

        <p>For user agents which support the
            <a class="eventtype" href="#event-type-DOMNodeInserted"><code>DOMNodeInserted</code></a>
          and
            <a class="eventtype" href="#event-type-DOMNodeRemoved"><code>DOMNodeRemoved</code></a>
          event types, this specification no longer requires that the event type be fired for
          <code>Attr</code> nodes.
          </p>

        <p>The <a href="#dfn-resize" class="eventtype internalDFN"><code>resize</code></a> event type no longer bubbles and the
          <a href="#dfn-mousemove" class="eventtype internalDFN"><code>mousemove</code></a> event is now cancelable, reflecting existing
          implementations.
          </p>
      </section>

      <section property="bibo:hasPart" resource="#changes-DOMLevel2to3Changes" typeof="bibo:Chapter" id="changes-DOMLevel2to3Changes">
        <h4 resource="#h-changes-domlevel2to3changes" id="h-changes-domlevel2to3changes"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1.3 </span>Changes to DOM Level 2 Events interfaces</span></h4>

        <dl>
          <dt>Interface <a href="#interface-Event"><code>Event</code></a></dt>
          <dd>The <a href="#interface-Event"><code>Event</code></a> interface has one new attribute,
              <a href="#widl-Event-defaultPrevented"><code>Event.defaultPrevented</code></a>,
            and one new method,
              <a href="#widl-Event-stopImmediatePropagation"><code>Event.stopImmediatePropagation()</code></a>.
            <br>
            <a href="#widl-Event-timeStamp"><code>Event.timeStamp</code></a> is now a <code>Number</code>
            in the ECMAScript binding.
            A proposed correction to make the same change in
              [<cite><a class="normative" href="#references-DOMCore">DOM3 Core</a></cite>] is forthcoming.
            <br>
            This specification considers the <a href="#widl-Event-type"><code>Event.type</code></a> attribute
            to be case-sensitive, while DOM Level 2 Events considers
            <a href="#widl-Event-type"><code>Event.type</code></a> to be case-insensitive.
            </dd>

          <dt>Interface <a href="#interface-EventTarget"><code>EventTarget</code></a></dt>
          <dd>The method <a href="#widl-EventTarget-dispatchEvent"><code>EventTarget.dispatchEvent()</code></a>
            was modified.
            </dd>

          <dt>Interface <a href="#interface-MouseEvent"><code>MouseEvent</code></a></dt>
          <dd>The <a href="#interface-MouseEvent"><code>MouseEvent</code></a> interface has one new method
            <a href="#widl-MouseEvent-getModifierState"><code>MouseEvent.getModifierState()</code></a>.
            </dd>

          <dt>Exception <code>EventException</code></dt>
          <dd>The exception <code>EventException</code> <a href="#note-eventexcpetion-removed">is removed in this
            specification</a>.
            The prior <code>DISPATCH_REQUEST_ERR</code> code is re-mapped to a <code>DOMException</code> of type
            <code>InvalidStateError</code>.
            </dd>
        </dl>
      </section>

      <section property="bibo:hasPart" resource="#changes-DOMLevel3Addons" typeof="bibo:Chapter" id="changes-DOMLevel3Addons">
        <h4 resource="#h-changes-domlevel3addons" id="h-changes-domlevel3addons"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.1.4 </span>New Interfaces</span></h4>

        <p>The interfaces
            <a href="#interface-CustomEvent"><code>CustomEvent</code></a>,
            <a href="#interface-FocusEvent"><code>FocusEvent</code></a>,
            <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>,
            <a href="#interface-CompositionEvent"><code>CompositionEvent</code></a>,
            and <a href="#interface-WheelEvent"><code>WheelEvent</code></a>
          were added to the Events module.
          </p>
      </section>
    </section>

    <section property="bibo:hasPart" resource="#changes-drafts" typeof="bibo:Chapter" id="changes-drafts">
      <h3 resource="#h-changes-drafts" id="h-changes-drafts"><span property="xhv:role" resource="xhv:heading"><span class="secno">F.2 </span>Changes between different drafts of UI Events (formerly DOM Level 3 Events)</span></h3>

      <p>The DOM Level 3 Events document was originally developed between 2000 and 2003, and published
        as a <abbr title="World Wide Web Consortium">W3C</abbr> Note, pending further feedback and interest from implementers.
        In 2006, it was picked up for revision and progress on the Recommendation Track, and was
        then revised to reflect the current state of implementation and the
        needs of script authors.
        </p>

      <p>Despite its status only as a <abbr title="World Wide Web Consortium">W3C</abbr> Note, rather than an official Recommendation, DOM 3 Events
        saw some implementation, and was also referenced by other specifications, so care
        is being taken to cause minimal disruption, while still adapting the specification to the
        current environment.
        </p>

      <p>The current specification has been reordered significantly from the earlier <abbr title="World Wide Web Consortium">W3C</abbr> Note form,
        and also from the structure of DOM2 Events, in order to clarify the material.
        New diagrams have been put in place to represent hierarchies and events flows more clearly.
        Here are some of the more important changes between drafts:
        </p>

      <ul>
        <li>The <q>key identifier</q> feature has been renamed <q>key value</q> to disambiguate
          them from unique identifiers for keys.
          </li>
        <li>The
            <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a>
          interface was briefly (from 2003-2010) defined to have <code>keyIdentifier</code>
          and <code>keyLocation</code> attributes, but these were removed in favor of the current
            <a href="#widl-KeyboardEvent-key"><code>key</code></a>
            and <a href="#widl-KeyboardEvent-location"><code>location</code></a>
          attributes. These attributes were not widely implemented.
          </li>
        <li>The <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> and
          <a href="#interface-CompositionEvent"><code>CompositionEvent</code></a> interfaces defined
          a <code>locale</code> attribute. This attribute was underspecified and moved to a separate
          specification [<a href="#references-UIEvents-old">UIEvents (Keyboard extensions)</a>].
          <span class="issue">Need to update this text once locale's locale is finalized</span></li>
        <li>The <a href="#interface-KeyboardEvent"><code>KeyboardEvent</code></a> also had a <code>char</code>
          attribute that was only used by the
            <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>
          event. Since the keypress event has been deprecated, this attribute was no longer useful
          and was removed.
          </li>
        <li>The <code>change</code>, <code>submit</code>, and <code>reset</code> events were removed,
          since they were specific to HTML forms, and are specified in
          [<cite><a class="informative" href="#references-HTML5">HTML5</a></cite>].
          </li>
        <li>The <code>textInput</code> event, originally proposed as a replacement for
          <a class="eventtype" href="#event-type-keypress"><code>keypress</code></a>, was
          removed in favor of the current
            <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-beforeinput"><code>beforeinput</code></a>
          and <a class="eventtype" href="http://w3c.github.io/editing-explainer/input-events.html#event-type-input"><code>input</code></a> events.
          </li>
        <li>Namespaced events have been removed.
          </li>
        <li>Updated to use <a href="#references-WebIDL">Web IDL</a>.
          </li>
        <li>EventException has been removed.
          </li>
      </ul>
    </section>
  </section>  <!-- changes-from-earlier-versions -->

  <!-- Appendix G: Acknowledgements ========================================================-->
  <section property="bibo:hasPart" resource="#acknowledgements-contributors" typeof="bibo:Chapter" id="acknowledgements-contributors">
    <!--OddPage--><h2 resource="#h-acknowledgements-contributors" id="h-acknowledgements-contributors"><span property="xhv:role" resource="xhv:heading"><span class="secno">G. </span>Acknowledgements</span></h2>

    <p class="1st">Many people contributed to the DOM specifications (Level 1, 2 or 3), including
      participants of the DOM Working Group, the DOM Interest Group,
      the WebAPI Working Group, and the WebApps Working Group.
      We especially thank the following:
      </p>

    <p>Andrew Watson (Object Management Group),
      Andy Heninger (IBM),
      Angel Diaz (IBM),
      Anne van Kesteren (Opera Software),
      Arnaud Le Hors (<abbr title="World Wide Web Consortium">W3C</abbr> and IBM),
      Arun Ranganathan (AOL),
      Ashok Malhotra (IBM and Microsoft),
      Ben Chang (Oracle),
      Bill Shea (Merrill Lynch),
      Bill Smith (Sun),
      Björn Höhrmann,
      Bob Sutor (IBM),
      Charles McCathie-Nevile (Opera Software, <em>Co-Chair</em>),
      Chris Lovett (Microsoft),
      Chris Wilson (Microsoft),
      Christophe Jolif (ILOG),
      David Brownell (Sun),
      David Ezell (Hewlett-Packard Company),
      David Singer (IBM),
      Dean Jackson (<abbr title="World Wide Web Consortium">W3C</abbr>, <em><abbr title="World Wide Web Consortium">W3C</abbr> Team Contact</em>),
      Dimitris Dimitriadis (Improve AB and invited expert),
      Don Park (invited),
      Doug Schepers (Vectoreal),
      Elena Litani (IBM),
      Eric Vasilik (Microsoft),
      Gavin Nicol (INSO),
      Gorm Haug Eriksen (Opera Software),
      Ian Davis (Talis Information Limited),
      Ian Hickson (Google),
      Ian Jacobs (<abbr title="World Wide Web Consortium">W3C</abbr>),
      James Clark (invited),
      James Davidson (Sun),
      Jared Sorensen (Novell),
      Jeroen van Rotterdam (X-Hive Corporation),
      Joe Kesselman (IBM),
      Joe Lapp (webMethods),
      Joe Marini (Macromedia),
      John Robinson (AOL),
      Johnny Stenback (Netscape/AOL),
      Jon Ferraiolo (Adobe),
      Jonas Sicking (Mozilla Foundation),
      Jonathan Marsh (Microsoft),
      Jonathan Robie (Texcel Research and Software AG),
      Kim Adamson-Sharpe (SoftQuad Software Inc.),
      Lauren Wood (SoftQuad Software Inc., <em>former Chair</em>),
      Laurence Cable (Sun),
      Luca Mascaro (HTML Writers Guild),
      Maciej Stachowiak (Apple Computer),
      Marc Hadley (Sun Microsystems),
      Mark Davis (IBM),
      Mark Scardina (Oracle),
      Martin Dürst (<abbr title="World Wide Web Consortium">W3C</abbr>),
      Mary Brady (NIST),
      Michael Shenfield (Research In Motion),
      Mick Goulish (Software AG),
      Mike Champion (Arbortext and Software AG),
      Miles Sabin (Cromwell Media),
      Patti Lutsky (Arbortext),
      Paul Grosso (Arbortext),
      Peter Sharpe (SoftQuad Software Inc.),
      Phil Karlton (Netscape),
      Philippe Le Hégaret (<abbr title="World Wide Web Consortium">W3C</abbr>, <em><abbr title="World Wide Web Consortium">W3C</abbr> Team Contact and former Chair</em>),
      Ramesh Lekshmynarayanan (Merrill Lynch),
      Ray Whitmer (iMall, Excite@Home, and Netscape/AOL, <em>Chair</em>),
      Rezaur Rahman (Intel),
      Rich Rollman (Microsoft),
      Rick Gessner (Netscape),
      Rick Jelliffe (invited),
      Rob Relyea (Microsoft),
      Robin Berjon (Expway, <em>Co-Chair</em>),
      Scott Hayman (Research In Motion),
      Scott Isaacs (Microsoft),
      Sharon Adler (INSO),
      Stéphane Sire (IntuiLab),
      Steve Byrne (JavaSoft),
      Tim Bray (invited),
      Tim Yu (Oracle),
      Tom Pixley (Netscape/AOL),
      T.V. Raman (Google).
      Vidur Apparao (Netscape) and
      Vinod Anupam (Lucent).
      </p>

    <p><strong>Former editors:</strong>
      Tom Pixley (Netscape Communications Corporation) until July 2002,
      Philippe Le Hégaret (<abbr title="World Wide Web Consortium">W3C</abbr>) until November 2003,
      Björn Höhrmann (Invited Expert) until January 2008,
      Doug Schepers (<abbr title="World Wide Web Consortium">W3C</abbr>) from March 2008 to May 2011,
      and Jacob Rossi (Microsoft) from March 2011 to October 2011.
      </p>

    <p><strong>Contributors:</strong>
      In the WebApps Working Group, the following people made substantial material contributions
      in the process of refining and revising this specification:
      Bob Lund (Cable Laboratories),
      Cameron McCormack (Invited Expert / Mozilla),
      Daniel Danilatos (Google),
      Gary Kacmarcik (Google),
      Glenn Adams (Samsung),
      Hallvord R. M. Steen (Opera),
      Hironori Bono (Google),
      Mark Vickers (Comcast),
      Masayuki Nakano (Mozilla),
      Olli Pettay (Mozilla),
      Takayoshi Kochi (Google) and
      Travis Leithead (Microsoft).
      </p>

    <p><strong>Glossary contributors:</strong>
      Arnaud Le Hors (<abbr title="World Wide Web Consortium">W3C</abbr>) and
      Robert S. Sutor (IBM Research).
      </p>

    <p><strong>Test suite contributors:</strong>
      Carmelo Montanez (NIST),
      Fred Drake,
      Mary Brady (NIST),
      Neil Delima (IBM),
      Rick Rivello (NIST),
      Robert Clary (Netscape),
      with a special mention to Curt Arnold.
      </p>

    <p>Thanks to all those who have helped to improve this specification by sending suggestions and
      corrections (please, keep bugging us with your issues!), or writing informative books or Web sites:
      Al Gilman,
      Alex Russell,
      Alexander J. Vincent,
      Alexey Proskuryakov,
      Arkadiusz Michalski,
      Brad Pettit,
      Cameron McCormack,
      Curt Arnold,
      David Flanagan,
      Dylan Schiemann,
      Erik Arvidsson,
      Garrett Smith,
      Giuseppe Pascale,
      James Su,
      Jan Goyvaerts (regular-expressions.info),
      Jorge Chamorro,
      Kazuyuki Ashimura,
      Ken Rehor,
      Magnus Kristiansen,
      Martijn Wargers,
      Martin Dürst,
      Michael B. Allen,
      Mike Taylor,
      Misha Wolf,
      Ojan Vafai,
      Oliver Hunt,
      Paul Irish,
      Peter-Paul Koch,
      Richard Ishida,
      Sean Hogan,
      Sergey Ilinsky,
      Sigurd Lerstad,
      Steven Pemberton,
      Tony Chang,
      William Edney and
      Øistein E. Andersen.
      </p>

    <section property="bibo:hasPart" resource="#acknowledgements-Productions" typeof="bibo:Chapter" id="acknowledgements-Productions">
      <h3 resource="#h-acknowledgements-productions" id="h-acknowledgements-productions"><span property="xhv:role" resource="xhv:heading"><span class="secno">G.1 </span>Production Systems</span></h3>

      <p>The current drafts of this specification are lovingly hand-crafted in HTML and SVG, using ReSpec
        and custom scripts to format the document according to <abbr title="World Wide Web Consortium">W3C</abbr> requirements.
        </p>

      <p>Earlier versions of this specification were written in XML — the HTML, OMG IDL, Java and
        ECMAScript bindings were all produced automatically.
        Thanks to Joe English, author of <code>cost</code>,
        which was used as the basis for producing DOM Level 1.
        Thanks also to Gavin Nicol, who wrote the scripts which run on top of cost.
        Arnaud Le Hors and Philippe Le Hégaret maintained the scripts.
        </p>

      <p>After DOM Level 1,
          <a class="normative" href="http://xerces.apache.org/xerces-j/">Xerces</a>
        was used as the basis DOM implementation and wish to thank the authors.
        Philippe Le Hégaret and Arnaud Le Hors wrote the
          <a class="normative" href="http://dev.w3.org/cvsweb/java/classes/org/w3c/tools/specgenerator/">Java programs</a>
        which are the <a class="def" href="#glossary-DOM-application">DOM application</a>.
        </p>

      <p>Thanks also to Jan Kärrman, author of
          <a class="normative" href="http://user.it.uu.se/~jan/html2ps.html">html2ps</a>,
        which was previously used to generate PostScript versions of the specification.
        </p>
    </section>  <!-- acknowledgements-Productions -->
  </section>  <!-- acknowledgements-contributors -->

  <!-- Appendix H: Glossary  ========================================================-->
  <section property="bibo:hasPart" resource="#glossary" typeof="bibo:Chapter" id="glossary">
    <!--OddPage--><h2 resource="#h-glossary" id="h-glossary"><span property="xhv:role" resource="xhv:heading"><span class="secno">H. </span>Glossary</span></h2>

    <p class="1st">Some of the following term definitions have been borrowed or modified from similar definitions in other <abbr title="World Wide Web Consortium">W3C</abbr> or standards documents. See the links within
      the definitions for more information.</p>

    <dl id="glossary-list">
      <dt id="glossary-activation-behavior"><dfn id="dfn-activation-behavior">activation behavior</dfn></dt>
      <dd>The action taken when an <a class="def" href="#glossary-event">event</a>, typically initiated by users through an input device, causes an element to fulfill a
        defined task.  The task <em title="MAY" class="rfc2119">MAY</em> be defined for that element by the <a class="def" href="#glossary-host-language">host language</a>, or by
        author-defined variables, or both.  The default task for any given element <em title="MAY" class="rfc2119">MAY</em> be a generic action, or <em title="MAY" class="rfc2119">MAY</em> be
        unique to that element.  For example, the activation behavior of an HTML or SVG <code>&lt;a&gt;</code> element is to cause the
        <a class="def" href="#glossary-user-agent">user agent</a> to traverse the link specified in the <code>href</code> attribute, with the further optional parameter
        of specifying the browsing context for the traversal (such as the current window or tab, a named window, or a new window). The activation behavior of an HTML
        <code>&lt;input&gt;</code> element with the <code>type</code> attribute value <code>submit</code> is be to send the values of the form elements to an
        author-defined IRI by the author-defined HTTP method.  See <a href="#event-flow-activation">Activation triggers and behavior</a> for more details.</dd>

      <dt id="glossary-activation-trigger"><dfn id="dfn-activation-trigger">activation trigger</dfn></dt>
      <dd>An event which is defined to initiate an <a class="def" href="#glossary-activation-behavior">activation behavior</a>.  Refer to <a href="#event-flow-activation">
        Activation triggers and behavior</a> for more details.</dd>

      <dt id="glossary-author"><dfn id="dfn-author">author</dfn></dt>
      <dd>In the context of this specification, an <em>author</em>, <em>content author</em>, or <em>script author</em> is a person who writes script or other executable
        content that uses the interfaces, events, and event flow defined in this specification.  See <a href="#conf-authors">Content authors and content</a>  conformance
        category for more details.</dd>

      <dt id="glossary-body-element"><dfn id="dfn-body-element">body element</dfn></dt>
      <dd>In HTML or XHTML documents, the body element represents the contents of the document. In a well-formed HTML document, the body element is a first descendant of
        the <a href="#glossary-root-element">root element</a>.</dd>

      <dt id="glossary-bubbling-phase"><dfn id="dfn-bubbling-phase">bubbling phase</dfn></dt>
      <dd>The process by which an <a class="def" href="#glossary-event">event</a> can be handled by one of the target's ancestors <em>after</em> being handled by the
        <a class="def" href="#glossary-event-target">event target</a>. See the description of the <a href="#bubble-phase">bubble phase</a> in the context
        of event flow for more details.</dd>

      <dt id="glossary-capture-phase"><dfn id="dfn-capture-phase">capture phase</dfn></dt>
      <dd>The process by which an <a class="def" href="#glossary-event">event</a> can be handled by one of the target's ancestors <em>before</em> being handled by the
        <a class="def" href="#glossary-event-target">event target</a>. See the description of the <a href="#capture-phase">capture phase</a> in the context
        of event flow for more details.</dd>

      <dt id="glossary-candidate-event-handlers"><dfn id="dfn-candidate-event-handlers">candidate event handlers</dfn></dt>
      <dt><dfn id="dfn-candidate-event-listeners">candidate event listeners</dfn></dt>
      <dd>The list of all <a class="def" href="#glossary-event-handler">event listeners</a> that have been registered on the target object in their order of registration. This
        list is captured or <q>frozen</q> before event listeners on the target object are dispatched, and released or <q>un-frozen</q> after this set of candidate event
        handlers have been dispatched (allowing these event listeners to add or remove additional listeners on other objects in an event's propagation chain, but not affect
        the order of listeners that will be invoked on the target object).

        <div class="note"><div id="h-note77" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> Initially capturing the candidate event handlers prevents infinite loops of event listener dispatch on a given target object.</p></div>
      </dd>

      <dt id="glossary-character-value"><dfn id="dfn-character-value">character value</dfn></dt>
      <dd>In the context of key values, a character value is a string representing one or more Unicode characters, such as a letter or symbol, or a set of letters. In this
        specification, character values are denoted as a unicode string (e.g., <code title="Character Value" class="char">'\u0020'</code>) or a glyph representation of the same code point (e.g.,
        <code title="Character Value Glyph" class="glyph">' '</code>), and are color coded to help distinguish these two representations.
        <div class="note"><div id="h-note78" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> In source code, some key values, such as non-graphic characters, can be represented using
        the character escape syntax of the programming language in use.</p></div>
      </dd>

      <dt id="glossary-current-event-target"><dfn id="dfn-current-event-target">current event target</dfn></dt>
      <dd>In an event flow, the current event target is the object associated with the <a class="def" href="#glossary-event-handler">event handler</a> that is currently being
        dispatched. This object <em title="MAY" class="rfc2119">MAY</em> be the <a href="#glossary-event-target">event target</a> itself or one of its ancestors. The current event target changes as the
        <a class="def" href="#glossary-event">event</a> propagates from object to object through the various <a class="def" href="#glossary-phase">phases</a> of the event flow.
        The current event target is the value of the <a href="#widl-Event-currentTarget"><code>Event.currentTarget</code></a> attribute.</dd>

      <dt id="glossary-dead-key"><dfn id="dfn-dead-key">dead key</dfn></dt>
      <dd>A dead key is a key or combination of keys which produces no character by itself, but which in combination or sequence with another key produces a modified character,
        such as a character with diacritical marks (e.g., <code title="Key Value" class="key">ö</code>, <code title="Key Value" class="key">é</code>, <code title="Key Value" class="key">â</code>).</dd>

      <dt id="glossary-default-action"><dfn id="dfn-default-action">default action</dfn></dt>
      <dd>A <a class="def" href="#glossary-default-action">default action</a> is an <em title="OPTIONAL" class="rfc2119">OPTIONAL</em> supplementary behavior that an implementation
        <em title="MUST" class="rfc2119">MUST</em> perform in combination with the dispatch of the event object.  Each event type definition, and each specification, defines the
        <a class="def" href="#glossary-default-action">default action</a> for that event type, if it has one.  An instance of an event <em title="MAY" class="rfc2119">MAY</em> have more than
        one <a class="def" href="#glossary-default-action">default action</a> under some circumstances, such as when associated with an
        <a class="def" href="#glossary-activation-trigger">activation trigger</a>.  A <a class="def" href="#glossary-default-action"> default action</a> <em title="MAY" class="rfc2119">MAY</em>
        be cancelled through the invocation of the <a href="#widl-Event-preventDefault"><code>Event.preventDefault()</code></a> method. For more details, see
        <a href="#event-flow-default-cancel">Default actions and cancelable events</a>.</dd>

      <dt id="glossary-delta"><dfn id="dfn-delta">delta</dfn></dt>
      <dd>The estimated scroll amount (in pixels, lines, or pages) that the user agent will scroll or zoom the page in response to the physical movement of an input device that
        supports the <code>WheelEvent</code> interface (such as a mouse wheel or touch pad). The value of a <a class="def" href="#glossary-delta">delta</a> (e.g., the <a href="#widl-WheelEvent-deltaX">deltaX</a>, <a href="#widl-WheelEvent-deltaY">deltaY</a>, or <a href="#widl-WheelEvent-deltaZ">deltaZ</a> attributes) is to be
        interpreted in the context of the current <a href="#widl-WheelEvent-deltaMode"><code>deltaMode</code></a> property. The relationship between the physical movement of
        a wheel (or other device) and whether the <a class="def" href="#glossary-delta">delta</a> is positive or negative is environment and device dependent. However, if a user
        agent scrolls as the <a class="def" href="#glossary-default-action">default action</a> then the sign of the <a class="def" href="#glossary-delta">delta</a> is given by a
        right-hand coordinate system where positive X,Y, and Z axes are directed towards the right-most edge, bottom-most edge, and farthest depth (away from the user) of the
        document, respectively.</dd>

      <dt id="glossary-deprecated"><dfn id="dfn-deprecated">deprecated</dfn></dt>
      <dd>Features marked as deprecated are included in the specification as reference to older implementations or specifications, but are <em title="OPTIONAL" class="rfc2119">OPTIONAL</em>
        and discouraged.  Only features which have existing or in-progress replacements <em title="MUST" class="rfc2119">MUST</em> be deprecated in this specification.  Implementations
        which do not already include support for the feature <em title="MAY" class="rfc2119">MAY</em> implement deprecated features for reasons of backwards compatibility with existing
        content, but content authors creating content <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em> use deprecated features, unless there is no other way to solve a use case.
        Other specifications which reference this specification <em title="SHOULD NOT" class="rfc2119">SHOULD NOT</em> use deprecated features, but <em title="SHOULD" class="rfc2119">SHOULD</em>
        point instead to the replacements of which the feature is deprecated in favor.  Features marked as deprecated in this specification are expected to be dropped from
        future specifications.</dd>

      <dt id="glossary-dispatch"><dfn id="dfn-dispatch">dispatch</dfn></dt>
      <dd>To create an event with attributes and methods appropriate to its type and context, and propagate it through the DOM tree in the specified manner. Interchangeable
        with the term <q><a href="#glossary-fire">fire</a></q>, e.g., <q>fire a <a class="eventtype" href="#event-type-click"><code>click</code></a> event</q> or <q>dispatch
        a <a class="eventtype" href="#event-type-load"><code>load</code></a> event</q>.</dd>

      <dt id="glossary-document"><dfn id="dfn-document">document</dfn></dt>
      <dd>An object instantiating the <a href="http://www.w3.org/TR/DOM-Level-3-Core/core.html#i-Document" title="Document Object Model Core"><code>Document</code> interface</a>
        [<cite><a class="normative" href="#references-DOMCore">DOM3 Core</a></cite>], representing the entire HTML or XML text document.  Conceptually, it is the root of
        the document tree, and provides the primary access to the document's data.</dd>

      <dt id="glossary-DOM-application"><dfn id="dfn-dom-application">DOM application</dfn></dt>
      <dd>A DOM application is script or code, written by a content author or automatically generated, which takes advantage of the interfaces, methods, attributes, events,
        and other features described in this specification in order to make dynamic or interactive content, such as Web applications, exposed to users in a <a class="def" href="#glossary-user-agent">user agent</a>.</dd>

      <dt id="glossary-DOM-Level-0"><dfn id="dfn-dom-level-0">DOM Level 0</dfn></dt>
      <dd>The term <q>DOM Level 0</q> refers to a mix of HTML document functionalities, often not formally specified but traditionally supported as de facto standards, implemented
        originally by Netscape Navigator version 3.0 or Microsoft Internet Explorer version 3.0.  In many cases, attributes or methods have been included for reasons of
        backward compatibility with <q>DOM Level 0</q>.</dd>

      <dt id="glossary-empty-string"><dfn id="dfn-empty-string">empty string</dfn></dt>
      <dd>The empty string is a value of type <code>DOMString</code> of length <code>0</code>, i.e., a string which contains no characters (neither printing nor control
        characters).</dd>

      <dt id="glossary-event"><dfn id="dfn-event">event</dfn></dt>
      <dd>An event is the representation of some occurrence (such as a mouse click on the presentation of an element, the removal of child node from an element, or any number
        of other possibilities) which is associated with its <a class="def" href="#glossary-event-target">event target</a>. Each event is an instantiation
        of one specific <a class="def" href="#glossary-event-type">event type</a>.</dd>

      <dt id="glossary-event-focus"><dfn id="dfn-event-focus">event focus</dfn></dt>
      <dd>Event focus is a special state of receptivity and concentration on an particular element or other <a class="def" href="#glossary-event-target">event target</a> within
        a document.  Each element has different behavior when focused, depending on its functionality, such as priming the element for activation (as for a button or hyperlink)
        or toggling state (as for a checkbox), receiving text input (as for a text form field), or copying selected text.  For more details, see <a href="#events-focusevent-doc-focus">
        Document Focus and Focus Context</a>.</dd>

      <dt id="glossary-event-focus-ring"><dfn id="dfn-event-focus-ring">event focus ring</dfn></dt>
      <dd>An event focus ring is an ordered set of <a class="def" href="#glossary-event-focus">event focus</a> targets within a document.  A <a class="def" href="#glossary-host-language">
        host language</a> <em title="MAY" class="rfc2119">MAY</em> define one or more ways to determine the order of targets, such as document order, a numerical index defined per focus target, explicit pointers
        between focus targets, or a hybrid of different models.  Each document <em title="MAY" class="rfc2119">MAY</em> contain multiple focus rings, or conditional focus rings.  Typically, for document-order
        or indexed focus rings, focus <q>wraps around</q> from the last focus target to the first.</dd>

      <dt id="glossary-event-handler"><dfn id="dfn-event-handler">event handler</dfn></dt>
      <dt><dfn id="dfn-event-listener">event listener</dfn></dt>
      <dd>An object that implements the <a href="#interface-EventListener"><code>EventListener</code></a> interface and provides an <a href="#widl-EventListener-handleEvent">
        <code>EventListener.handleEvent()</code></a> callback method. Event handlers are language-specific. Event handlers are invoked in the context of a particular object
        (the <a class="def" href="#glossary-current-event-target">current event target</a>) and are provided with the event object itself.

        <div class="note"><div id="h-note79" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class=""><strong>Note: </strong>In JavaScript, user-defined functions are considered to implement the <a href="#interface-EventListener"><code>EventListener</code></a> interface. Thus the
          event object will be provided as the first parameter to the user-defined function when it is invoked. Additionally, JavaScript objects can also implement
          the <a href="#interface-EventListener"><code>EventListener</code></a> interface when they define a <a href="#widl-EventListener-handleEvent"><code>handleEvent</code></a> method.</p></div>
      </dd>

      <dt id="glossary-event-order"><dfn id="dfn-event-order">event order</dfn></dt>
      <dd>The sequence in which events from the same event source or process occur, using the same or related event interfaces. For example, in an environment with a mouse,
        a track pad, and a keyboard, each of those input devices would constitute a separate event source, and each would follow its own event order. A <a class="eventtype" href="#event-type-mousedown"><code>mousedown</code></a> event from the trackpad followed by a <a class="eventtype" href="#event-type-mouseup"><code>mouseup</code></a>
        event from the mouse would not result in a <a class="eventtype" href="#event-type-click"><code>click</code></a> event.

        <div class="note"><div id="h-note80" role="heading" aria-level="3" class="note-title"><span>Note</span></div><p class=""><strong>Note:</strong> There can be interactions between different event orders. For example, a <a class="eventtype" href="#event-type-click"><code>click</code></a> event might
        be modified by a concurrent <a class="eventtype" href="#event-type-keydown"><code>keydown</code></a> event (<code title="Key Value" class="key">'Shift'</code><code>+click</code>). However, the event orders
        of these different event sources would be distinct.</p></div>

        The event order of some interfaces are device-independent. For example, a user might change focus using the <code title="Key Value" class="key">'Tab'</code>
        key, or by clicking the new focused element with the mouse.  The event order in such cases depends on the state of the process, not on the state of the device that
        initiates the state change.</dd>

      <dt id="glossary-event-phase"><dfn id="dfn-event-phase">event phase</dfn></dt>
      <dd>See <a class="def" href="#glossary-phase">phase</a>.</dd>

      <dt id="glossary-event-target"><dfn id="dfn-event-target">event target</dfn></dt>
      <dd>The object to which an <a class="def" href="#glossary-event">event</a> is targeted using the <a href="#event-flow">DOM event flow</a>. The event target is the
        value of the <a href="#widl-Event-target"><code>Event.target</code></a> attribute.</dd>

      <dt id="glossary-event-type"><dfn id="dfn-event-type">event type</dfn></dt>
      <dd>An <em>event type</em> is an <a class="def" href="#glossary-event">event</a> object with a particular name and which defines particular trigger conditions, properties,
        and other characteristics which distinguish it from other event types.  For example, the <a class="eventtype" href="#event-type-click"><code>click</code></a> event
        type has different characteristics than the <a class="eventtype" href="#event-type-mouseover"><code>mouseover</code></a> or <a class="eventtype" href="#event-type-load">
        <code>load</code></a> event types. The event type is exposed as the <a href="#widl-Event-type"><code class="interface-attribute">Event.type</code></a>
        attribute on the event object.  See <a href="#event-types">event types</a> for more details.  Also loosely referred to as <em>'event'</em>, such as the <em><a class="eventtype" href="#event-type-click"><code>click</code></a> event</em>.</dd>

      <dt id="glossary-fire"><dfn id="dfn-fire">fire</dfn></dt>
      <dd>A synonym for <a href="#glossary-dispatch">dispatch</a>.</dd>

      <dt id="glossary-host-language"><dfn id="dfn-host-language">host language</dfn></dt>
      <dd>Any language which integrates the features of another language or API specification, while normatively referencing the origin specification rather than redefining
        those features, and extending those features only in ways defined by the origin specification.  An origin specification typically is only intended to be implemented
        in the context of one or more host languages, not as a standalone language.  For example, XHTML, HTML, and SVG are host languages for UI Events, and they integrate
        and extend the objects and models defined in this specification.</dd>

      <dt id="glossary-hysteresis"><dfn id="dfn-hysteresis">hysteresis</dfn></dt>
      <dd>A feature of human interface design to accept input values within a certain range of location or time, in order to improve the user experience.  For example, allowing
        for small deviation in the time it takes for a user to double-click a mouse button is temporal hysteresis, and not immediately closing a nested menu if the user
        mouses out from the parent window when transitioning to the child menu is locative hysteresis.</dd>

      <dt id="glossary-ime"><dfn id="dfn-ime">IME</dfn></dt>
      <dt id="glossary-input-method-editor"><dfn id="dfn-input-method-editor">input method editor</dfn></dt>
      <dd>An <em>input method editor</em> (IME), also known as a <em>front end processor</em>, is an application that performs the conversion between keystrokes and ideographs
        or other characters, usually by user-guided dictionary lookup, often used in East Asian languages (e.g., Chinese, Japanese, Korean).  An <a class="def" href="#glossary-ime">
        IME</a> <em title="MAY" class="rfc2119">MAY</em> also be used for dictionary-based word completion, such as on mobile devices.  See <a href="#keys-IME">Input Method Editors</a> for treatment of
        IMEs in this specification.  See also <a class="def" href="#glossary-text-composition-system">text composition system</a>.</dd>

      <dt id="glossary-key-mapping"><dfn id="dfn-key-mapping">key mapping</dfn></dt>
      <dd>Key mapping is the process of assigning a key value to a particular key, and is the result of a combination of several factors, including the operating system
        and the keyboard layout (e.g., <a class="def" href="#glossary-qwerty">QWERTY</a>, Dvorak, Spanish, InScript, Chinese, etc.), and after taking into account all <a class="def" href="#glossary-modifier-key">modifier key</a> (<code title="Key Value" class="key">'Shift'</code>, <code title="Key Value" class="key">'Alt'</code>, etc.) and
        <a class="def" href="#glossary-dead-key">dead key</a> states.</dd>

      <dt id="glossary-key-value"><dfn id="dfn-key-value">key value</dfn></dt>
      <dd>A key value is a <a class="def" href="#glossary-character-value">character value</a> or multi-character string (such as <code title="Key Value" class="key">'Enter'</code>,
        <code title="Key Value" class="key">'Tab'</code>, or <code title="Key Value" class="key">'MediaTrackNext'</code>) associated
        with a key in a particular state. Every key has a key value, whether or not it has a <a class="def" href="#glossary-character-value">character value</a>. This includes
        control keys, function keys, <a class="def" href="#glossary-modifier-key">modifier keys</a>, <a class="def" href="#glossary-dead-key">dead keys</a>, and any other key.
        The key value of any given key at any given time depends upon the <a class="def" href="#glossary-key-mapping">key mapping</a>.</dd>

      <dt id="glossary-localname"><dfn id="dfn-local-name">local name</dfn></dt>
      <dd>See local name in [<cite><a class="informative" href="#references-Namespaces10">XML Namespaces 1.0</a></cite>].</dd>

      <dt id="glossary-modifier-key"><dfn id="dfn-modifier-key">modifier key</dfn></dt>
      <dd>A modifier key changes the normal behavior of a key, such as to produce a character of a different case (as with the <code title="Key Value" class="key">'Shift'</code>
        key), or to alter what functionality the key triggers (as with the <code title="Key Value" class="key">'Fn'</code> or <code title="Key Value" class="key">'Alt'</code>
        keys). Refer to <a href="#keys-modifiers">Modifier keys</a>
        for a list of modifier keys.</dd>

      <dt id="glossary-namespaceURI"><dfn id="dfn-namespace-uri">namespace URI</dfn></dt>
      <dd>A <em>namespace URI</em> is a URI that identifies an XML namespace. This is called the namespace name in [<cite><a class="informative" href="#references-Namespaces10">XML
        Namespaces 1.0</a></cite>]. See also sections 1.3.2 <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-Core/core.html#baseURIs-Considerations"><em>DOM URIs</em></a>
        and 1.3.3 <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-Core/core.html#Namespaces-Considerations"><em>XML Namespaces</em></a> regarding URIs and namespace
        URIs handling and comparison in the DOM APIs.</dd>

      <dt id="glossary-phase"><dfn id="dfn-phase">phase</dfn></dt>
      <dd>In the context of <a class="def" href="#glossary-event">events</a>, a phase is set of logical traversals from node to node along the DOM tree, from the <a class="def" href="#glossary-window">Window</a> to the <code>Document</code> object, <a class="def" href="#glossary-root-element">root element</a>, and down
        to the <a class="def" href="#glossary-event-target">event target</a> (<a class="def" href="#glossary-capture-phase">capture phase</a>), at the <a class="def" href="#glossary-event-target">
        event target</a> itself (<a class="def" href="#glossary-target-phase">target phase</a>), and back up the same chain (<a class="def" href="#glossary-bubbling-phase">bubbling
        phase</a>).</dd>

      <dt id="glossary-propagation-path"><dfn id="dfn-propagation-path">propagation path</dfn></dt>
      <dd>The ordered set of <a class="def" href="#glossary-current-event-target">current event targets</a> though which an <a class="def" href="#glossary-event">event</a> object will pass
        sequentially on the way to and back from the <a class="def" href="#glossary-event-target">event target</a>.  As the event propagates, each <a class="def" href="#glossary-current-event-target">current event target</a> in the propagation path is in turn set as the <a href="#widl-Event-currentTarget"><code>Event.currentTarget</code></a>.
        The propagation path is initially composed of one or more <a class="def" href="#glossary-event-phase">event phases</a> as defined by the <a class="def" href="#glossary-event-type">
        event type</a>, but <em title="MAY" class="rfc2119">MAY</em> be interrupted.  Also known as an <em>event target chain</em>.</dd>

      <dt id="glossary-qwerty"><dfn id="dfn-qwerty">QWERTY</dfn></dt>
      <dd>QWERTY (pronounced <q>ˈkwɜrti</q>) is a common keyboard layout, so named because the first five character keys on the top row of letter keys are Q,
        W, E, R, T, and Y.  There are many other popular keyboard layouts (including the Dvorak and Colemak layouts), most designed for localization or ergonomics.</dd>

      <dt id="glossary-root-element"><dfn id="dfn-root-element">root element</dfn></dt>
      <dd>The first element node of a document, of which all other elements are children. The document element.</dd>

      <dt id="glossary-rotation"><dfn id="dfn-rotation">rotation</dfn></dt>
      <dd>An indication of incremental change on an input device using the <a href="#interface-WheelEvent">WheelEvent</a> interface. On some devices this <em title="MAY" class="rfc2119">MAY</em> be a literal
        rotation of a wheel, while on others, it <em title="MAY" class="rfc2119">MAY</em> be movement along a flat surface, or pressure on a particular button.</dd>

      <dt id="glossary-target-phase"><dfn id="dfn-target-phase">target phase</dfn></dt>
      <dd>The process by which an <a class="def" href="#glossary-event">event</a> can be handled by the <a class="def" href="#glossary-event-target">event target</a>.
        See the description of the <a href="#target-phase">target phase</a> in the context of event flow for more details.</dd>

      <dt id="glossary-text-composition-system"><dfn id="dfn-text-composition-system">text composition system</dfn></dt>
      <dd>A software component that interprets some form of alternate input (such as a <a class="def" href="#glossary-ime">input method editor</a>, a speech processor, or
        a handwriting recognition system) and converts it to text.</dd>

      <dt id="glossary-topmost-event-target"><dfn id="dfn-topmost-event-target">topmost event target</dfn></dt>
      <dd>The <a class="def" href="#glossary-topmost-event-target">topmost event target</a> <em title="MUST" class="rfc2119">MUST</em> be the element highest in the rendering order which is capable of being
        an <a class="def" href="#glossary-event-target">event target</a>. In graphical user interfaces this is the element under the user's pointing device. A user
        interface's <q>hit testing</q> facility is used to determine the target. For specific details regarding hit testing and stacking order, refer to the
        <a class="def" href="#glossary-host-language">host language</a>.</dd>

      <dt id="glossary-tree"><dfn id="dfn-tree">tree</dfn></dt>
      <dd>A data structure that represents a document as a hierarchical set of nodes with child-parent-sibling relationships, i.e., each node having one or more possible
        ancestors (nodes higher in the hierarchy in a direct lineage), one or more possible descendants (nodes lower in the hierarchy in a direct lineage), and one or more
        possible peers (nodes of the same level in the hierarchy, with the same immediate ancestor).</dd>

      <dt id="glossary-Unicode-character-categories"><dfn id="dfn-unicode-character-categories">Unicode character categories</dfn></dt>
      <dd>A subset of the General Category values that are defined for each Unicode code point. This subset contains all the
        Letter (<abbr title="Letter, Lowercase">Ll</abbr>,
          <abbr title="Letter, Modifier">Lm</abbr>,
          <abbr title="Letter, Other">Lo</abbr>,
          <abbr title="Letter, Titlecase">Lt</abbr>,
          <abbr title="Letter, Uppercase">Lu</abbr>),
        Number (<abbr title="Number, Decimal Digit">Nd</abbr>,
          <abbr title="Number, Letter">Nl</abbr>,
          <abbr title="Number, Other">No</abbr>),
        Punctuation (<abbr title="Punctuation, Connector">Pc</abbr>,
          <abbr title="Punctuation, Dash">Pd</abbr>,
          <abbr title="Punctuation, Close">Pe</abbr>,
          <abbr title="Punctuation, Final quote">Pf</abbr>,
          <abbr title="Punctuation, Initial quote">Pi</abbr>,
          <abbr title="Punctuation, Other">Po</abbr>,
          <abbr title="Punctuation, Open">Ps</abbr>)
        and Symbol (<abbr title="Symbol, Currency">Sc</abbr>,
          <abbr title="Symbol, Modifier">Sk</abbr>,
          <abbr title="Symbol, Math">Sm</abbr>,
          <abbr title="Symbol, Other">So</abbr>)
        category values.</dd>

      <dt id="glossary-unicode-code-point"><dfn id="dfn-unicode-code-point">Unicode code point</dfn></dt>
      <dd>A Unicode code point is a unique hexadecimal number signifying a character by its index in the Unicode codespace (or library of characters).  In the context of
        key values, a Unicode code point is expressed as a string in the format <code>\u</code> followed by a hexadecimal character index in the range <code>0000</code>
        to <code>10FFFF</code>, using at least four digits. See also <a class="def" href="#glossary-character-value">character value</a>.</dd>

      <dt id="glossary-un-initialized-value"><dfn id="dfn-un-initialized-value">un-initialized value</dfn></dt>
      <dd>The value of any event attribute (such as <a href="#widl-Event-bubbles"><code>Event.bubbles</code></a> or <a href="#widl-Event-currentTarget"><code>
        Event.currentTarget</code></a>) before the event has been initialized with <a href="#widl-Event-initEvent"><code>Event.initEvent()</code></a>. The un-initialized
        values of an event apply immediately after a new event has been created using the method <a href="#widl-DocumentEvent-createEvent"><code>
        DocumentEvent.createEvent()</code></a>.</dd>

      <dt id="glossary-user-agent"><dfn id="dfn-user-agent">user agent</dfn></dt>
      <dd>A program, such as a browser or content authoring tool, normally running on a client machine, which acts on a user's behalf in retrieving, interpreting, executing,
        presenting, or creating content.  Users <em title="MAY" class="rfc2119">MAY</em> act on the content using different user agents at different times, for different purposes.  See the <a href="#conf-interactive-ua">
        Web browsers and other dynamic or interactive user agents</a> and <a href="#conf-author-tools">Authoring tools</a> for details on the requirements for a <em>conforming</em>
        user agent.</dd>

      <dt id="glossary-window"><dfn id="dfn-window">Window</dfn></dt>
      <dd>The <code>Window</code> is the object referred to by the current document's browsing context's Window Proxy object as defined in <a href="http://www.w3.org/TR/html5/browsers.html#windowproxy" title="HTML5 WindowProxy description">HTML5</a> [<cite><a class="normative" href="#references-HTML5">HTML5</a></cite>].</dd>
    </dl>
  </section>  <!-- glossary -->

  <!-- Appendix I: References ========================================================-->
  <section property="bibo:hasPart" resource="#references" typeof="bibo:Chapter" id="references">
    <!--OddPage--><h2 resource="#h-references" id="h-references"><span property="xhv:role" resource="xhv:heading"><span class="secno">I. </span>References</span></h2>

    <p>For the latest version of any <abbr title="World Wide Web Consortium">W3C</abbr> specification please consult the list of
      <a class="normative" href="http://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> Technical Reports</a>
      available at http://www.w3.org/TR/.
      </p>

    <section property="bibo:hasPart" resource="#references-References-Normative" typeof="bibo:Chapter" id="references-References-Normative">
      <h3 resource="#h-references-references-normative" id="h-references-references-normative"><span property="xhv:role" resource="xhv:heading"><span class="secno">I.1 </span>Normative References</span></h3>

      <dl>
        <dt id="ref-BCP-47"><strong>[BCP-47]</strong> Best Current Practice 47: Tags for Identifying Languages</dt>
        <dd>A. Phillips, M. Davis, Editors,<br>
          September 2009.<br>
          The specification for describing the structure, content, construction, and semantics of language tags
          to indicate the human language used.
          Available at <a href="http://www.rfc-editor.org/rfc/bcp/bcp47.txt">http://www.rfc-editor.org/rfc/bcp/bcp47.txt</a>.
          </dd>

        <dt id="references-DOM2Events"><strong>[DOM2 Events]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113/">Document Object Model Level 2 Events Specification</a></cite>,<br>
          T. Pixley, Editor.<br>
          World Wide Web Consortium, November 2000.<br>
          This version of the Document Object Model Level 2 Events Specification is http://www.w3.org/TR/2000/REC-DOM-Level-2-Events-20001113.<br>
          The <a class="normative" href="http://www.w3.org/TR/DOM-Level-2-Events/">latest version of Document Object Model Level 2 Events</a>
          is available at http://www.w3.org/TR/DOM-Level-2-Events/.
          </dd>

        <dt id="references-DOMCore"><strong>[DOM3 Core]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/">Document Object Model Level 3 Core Specification</a></cite>,<br>
          A. Le Hors, et al., Editors.<br>
          World Wide Web Consortium, April 2004.<br>
          This version of the Document Object Model Level 3 Core Specification is http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/.<br>
          The <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-Core/">latest version of DOM Level 3 Core</a>
          is available at http://www.w3.org/TR/DOM-Level-3-Core/.
          </dd>

        <dt id="references-D3E-code"><strong>[DOM3 code Values]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/DOM-Level-3-Events-code/">DOM Level 3 KeyboardEvent code Values</a></cite>,<br>
          G. Kacmarcik, T. Leithead, Editors.<br>
          World Wide Web Consortium, April 2014.<br>
          This version of the DOM Level 3 KeyboardEvent code Values is http://www.w3.org/TR/DOM-Level-3-Events-code/.<br>
          </dd>

        <dt id="references-D3E-key"><strong>[DOM3 key Values]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/DOM-Level-3-Events-key/">DOM Level 3 KeyboardEvent key Values</a></cite>,<br>
          G. Kacmarcik, T. Leithead, Editors.<br>
          World Wide Web Consortium, April 2014.<br>
          This version of the DOM Level 3 KeyboardEvent key Values is http://www.w3.org/TR/DOM-Level-3-Events-key/.<br>
          </dd>

        <dt id="references-ECMAScript"><strong>[ECMAScript]</strong></dt>
        <dd><cite><a href="http://ecma-international.org/ecma-262/5.1/">ECMAScript Language Specification</a></cite>,<br>
          5.1 Edition.<br>
          European Computer Manufacturers Association, Standard ECMA-262, June 2011.<br>
          This version of the ECMAScript Language is available from http://ecma-international.org/ecma-262/5.1/.
          </dd>

        <dt id="references-HTML5"><strong>[HTML5]</strong></dt>
        <dd><cite class="w3cwd"><a href="http://www.w3.org/TR/2014/REC-html5-20141028/">HTML 5</a></cite>,<br>
          I. Hickson, Editor.<br>
          World Wide Web Consortium, <abbr title="World Wide Web Consortium">W3C</abbr> Recommendation, October 2014.<br>
          This edition of HTML 5 is http://www.w3.org/TR/2014/REC-html5-20141028/.<br>
          The <a href="http://www.w3.org/TR/html5/">latest edition of HTML 5</a> is available at http://www.w3.org/TR/html5/.
          </dd>

        <dt id="references-Java"><strong>[Java]</strong></dt>
        <dd><cite><a href="http://www.oracle.com/technetwork/java/index.html">The Java Language Specification</a></cite>,<br>
          J. Gosling, B. Joy, and G. Steele, Authors.<br>
          Addison-Wesley, September 1996.<br>
          Available at http://java.sun.com/docs/books/jls.
          </dd>

        <!-- Automatically assigned id="RFC2119". -->
        <dt id="RFC2119"><strong>[RFC2119]</strong> Key words for use in RFCs to indicate Requirement Levels</dt>
        <dd>S Bradner, 1997.<br>
          The specification for how to use English to specify normativity, as if it were a technical language.
          Available at <a href="http://www.ietf.org/rfc/rfc2119.txt"> http://www.ietf.org/rfc/rfc2119.txt</a>.
          </dd>

        <dt id="references-UnicodeNormalization"><strong>[UAX #15]</strong></dt>
        <dd><cite><a href="http://www.unicode.org/reports/tr15/">Unicode Normalization Forms</a></cite>,<br>
          The Unicode Standard Annex #15. The Unicode Consortium, 2006.<br>
          The latest version of this annex is available at http://www.unicode.org/reports/tr15/.
          </dd>

        <dt id="references-InputEvent"><strong>[InputEvents]</strong></dt>
        <dd><cite><a href="http://w3c.github.io/editing-explainer/input-events.html">Input Events</a></cite>,<br>
          Ben Peters, Editor.<br>
          Not yet published.
          </dd>

        <dt id="references-UIEvents-old"><strong>[UIEvents]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2014/WD-uievents-20140612/">UI Events</a></cite>,<br>
          G. Kacmarcik, T. Leithead, Editors.<br>
          World Wide Web Consortium, <span class="wip"><abbr title="World Wide Web Consortium">W3C</abbr> Working Group Note</span>, 12 June 2014.
          </dd>

        <dt id="references-Unicode"><strong>[Unicode]</strong></dt>
        <dd><cite>The Unicode Standard, Version 5.0</cite>,<br>
          ISBN 0-321-48091-0, as updated periodically by the publication of new versions.<br>
          See also <a class="normative" href="http://www.unicode.org/standard/versions/">Versions of the Unicode Standard</a>,
          available at http://www.unicode.org/standard/versions/ for
          latest version and additional information on versions of the standard and of the Unicode Character Database.
          </dd>

        <dt id="references-WebIDL"><strong>[WEB IDL]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/WebIDL/">Web IDL</a></cite>,<br>
          C. McCormack. 19 April 2012.<br>
          This version of the Web IDL Candidate Recommendation is: http://www.w3.org/TR/2012/CR-WebIDL-20120419/.<br>
          The <a href="http://heycam.github.io/webidl/">latest version of Web IDL</a> is available at
          http://heycam.github.io/webidl/.
          </dd>

        <dt id="references-Namespaces10"><strong>[XML Namespaces 1.0]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2006/REC-xml-names-20060816/">Namespaces in XML 1.0</a></cite>,<br>
          T. Bray, D. Hollander, A. Layman, and R. Tobin, Editors.<br>
          World Wide Web Consortium, 16 August 2006.<br>
          This version of the Namespaces in XML 1.0 Specification is http://www.w3.org/TR/2006/REC-xml-names-20060816.<br>
          The <a class="normative" href="http://www.w3.org/TR/xml-names/">latest version of Namespaces in XML 1.0</a>
          is available at http://www.w3.org/TR/xml-names/.
          </dd>
      </dl>
    </section>

    <section property="bibo:hasPart" resource="#references-References-Informative" typeof="bibo:Chapter" id="references-References-Informative">
      <h3 resource="#h-references-references-informative" id="h-references-references-informative"><span property="xhv:role" resource="xhv:heading"><span class="secno">I.2 </span>Informative References</span></h3>
      <dl>
        <dt id="ref-ARIA"><strong>[ARIA]</strong></dt>
        <dd><cite class="w3cwd"><a href="http://www.w3.org/TR/2009/WD-wai-aria-20091215/">Accessible Rich Internet Applications (WAI-ARIA) Version 1.0</a></cite>,<br>
          J. Craig, M. Cooper, R. Schwerdtfeger, L. Seeman, L. Pappas, Editors.<br>
          World Wide Web Consortium, 18 January 2011.<br>
          This version of the WAI-ARIA Candidate Recommendation is http://www.w3.org/TR/2011/CR-wai-aria-20110118/.<br>
          The <a href="http://www.w3.org/TR/wai-aria/">latest edition of WAI-ARIA</a> is available at http://www.w3.org/TR/wai-aria/.
          </dd>

        <dt id="references-CSS2"><strong>[CSS2.1]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2011/REC-CSS2-20110607/">Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification</a></cite>,<br>
          B. Bos, T. Çelik, I. Hickson, H.W. Lie, Editors.<br>
          World Wide Web Consortium, 07 June 2011.<br>
          This version of the CSS 2.1 Recommendation is http://www.w3.org/TR/2011/REC-CSS2-20110607/.<br>
          The <a class="normative" href="http://www.w3.org/TR/CSS2/">latest version of CSS 2.1</a> is available at http://www.w3.org/TR/CSS2/.
          </dd>

        <dt id="references-DOMRange"><strong>[DOM2 Range]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/DOM-Level-2-Traversal-Range/">Document Object Model (DOM) Level 2 Traversal and Range Specification</a></cite>,<br>
          J. Kesselman, J. Robie, M. Champion, P. Sharpe, V. Apparao, L. Wood, Editors.<br>
          World Wide Web Consortium, November 2000.
          </dd>

        <dt id="references-DOMLS"><strong>[DOM3 Load and Save]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407/">Document Object Model Level 3 Load and Save Specification</a></cite>,<br>
          J. Stenback, A. Heninger, Editors.<br>
          World Wide Web Consortium, April 2004.<br>
          This version of the DOM Level 3 Load and Save Specification is http://www.w3.org/TR/2004/REC-DOM-Level-3-LS-20040407/.<br>
          The <a class="normative" href="http://www.w3.org/TR/DOM-Level-3-LS/">latest version of DOM Level 3 Load and Save</a>
          is available at http://www.w3.org/TR/DOM-Level-3-LS/.
          </dd>

        <dt id="references-DOM4"><strong>[DOM4]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/dom/"><abbr title="World Wide Web Consortium">W3C</abbr> DOM4</a></cite>,<br>
          A. van Kesteren, A. Gregor, Ms2ger, Alex Russell, Robin Berjon, Editors.<br>
          World Wide Web Consortium, <span class="wip">Working Draft</span>, 10 July 2014.
          </dd>

        <dt id="references-DWW95"><strong>[DWW95]</strong></dt>
        <dd><cite>Developing International Software for Windows 95 and Windows NT: A Handbook for International Software Design</cite>,<br>
          N. Kano, Author.<br>
          Microsoft Press, 1995. ISBN 1-55615-840-8.
          </dd>

        <dt id="references-HTML40"><strong>[HTML 4.01]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/1999/REC-html401-19991224/">HTML 4.01 Specification</a></cite>,<br>
          D. Raggett, A. Le Hors, and I. Jacobs, Editors.<br>
          World Wide Web Consortium, December 1999.<br>
          This version of the HTML 4.01 Recommendation is http://www.w3.org/TR/1999/REC-html401-19991224.<br>
          The <a class="normative" href="http://www.w3.org/TR/html4/">
          latest version of HTML 4</a> is available at http://www.w3.org/TR/html4/.
          </dd>

        <dt id="references-HTMLEd"><strong>[HTML Editing]</strong></dt>
        <dd><cite><a href="https://dvcs.w3.org/hg/editing/raw-file/tip/editing.html">HTML Editing APIs</a></cite>,<br>
          A. Gregor, Editor.<br>
          World Wide Web Consortium, <span class="wip">work in progress</span>, 13 February 2014.
          </dd>

        <dt id="references-KeyProps"><strong>[KeyProps]</strong></dt>
        <dd><cite class="w3cwd"><a href="https://dvcs.w3.org/hg/dom3events/raw-file/tip/html/Note-KeyProps.html">Legacy Keyboard Event Properties</a></cite>,<br>
          D. Schepers, Editor.<br>
          World Wide Web Consortium, <span class="wip">work in progress</span>, 04 August 2010.<br>
          This edition of Legacy Keyboard Event Properties is https://dvcs.w3.org/hg/dom3events/raw-file/tip/html/Note-KeyProps.html.<br>
          The <a href="https://dvcs.w3.org/hg/dom3events/raw-file/tip/html/Note-KeyProps.html">latest edition of Legacy Keyboard Event Properties</a>
          is available at https://dvcs.w3.org/hg/dom3events/raw-file/tip/html/Note-KeyProps.html.
          </dd>

        <dt id="references-pcre"><strong>[PCRE]</strong></dt>
        <dd><cite><a href="http://www.pcre.org/">Perl Compatible Regular Expressions library</a></cite>.<br>
          Available at http://www.pcre.org/.
          </dd>

        <dt id="ref-rfc20"><strong>[RFC20]</strong> <abbr title="American Standard Code for Information Interchange">ASCII</abbr> format for Network Interchange</dt>
        <dd>V. Cerf, 1969.<br>
          Available at <a href="http://tools.ietf.org/rfc/rfc20.txt">http://tools.ietf.org/rfc/rfc20.txt</a>
          </dd>

        <dt id="ref-US-ASCII"><strong>[US-<abbr title="American Standard Code for Information Interchange">ASCII</abbr>]</strong> Coded Character Set - 7-Bit American Standard Code for Information Interchange</dt>
        <dd>Standard ANSI X3.4-1986, ANSI, 1986.
          </dd>

        <dt id="references-UAAG2"><strong>[UAAG 2.0]</strong></dt>
        <dd><cite><a href="http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100308/">User Agent Accessibility Guidelines (UAAG) 2.0</a></cite>,<br>
          J. Allan, K. Ford, J. Richards, J. Spellman, Editors.<br>
          World Wide Web Consortium, <span class="wip">work in progress</span>, 8 March 2010.<br>
          This version of the UAAG 2.0 specfication is http://www.w3.org/WAI/UA/2010/ED-UAAG20-20100308/.<br>
          The <a class="normative" href="http://www.w3.org/TR/UAAG20/">latest version of UAAG 2.0</a> is available at http://www.w3.org/TR/UAAG20/.
          </dd>

        <dt id="ref-WIN1252"><strong>[WIN1252]</strong></dt>
        <dd><a href="http://www.microsoft.com/globaldev/reference/sbcs/1252.htm">Windows 1252</a> a Coded Character Set - 8-Bit.<br>
          Microsoft Corporation.
          </dd>

        <dt id="ref-xforms"><strong>[XFORMS]</strong></dt>
        <dd><cite class="w3crec"><a href="http://www.w3.org/TR/2009/REC-xforms-20091020/">XForms 1.1</a></cite>,<br>
          J. Boyer, Editor.<br>
          World Wide Web Consortium, <span class="wip">work in progress</span>, 20 October 2009.<br>
          This edition of XForms 1.1 is http://www.w3.org/TR/2009/REC-xforms-20091020/.<br>
          The <a href="http://www.w3.org/TR/xforms/">latest edition of XForms</a> is available at http://www.w3.org/TR/xforms/.
          </dd>

        <dt id="references-XML"><strong>[XML 1.0]</strong></dt>
        <dd><cite><a href="http://www.w3.org/TR/2006/REC-xml-20060816/">Extensible Markup Language (XML) 1.0</a></cite>,<br>
          T. Bray, J. Paoli, C. M. Sperberg-McQueen, et. al, Editors.<br>
          World Wide Web Consortium, August 2006.<br>
          This version of the XML 1.0 Recommendation is http://www.w3.org/TR/2006/REC-xml-20060816/.<br>
          The <a class="normative" href="http://www.w3.org/TR/xml/">latest version of XML 1.0</a> is available at http://www.w3.org/TR/xml/.
          </dd>
      </dl>
    </section>
  </section>  <!-- references -->


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