fullscreen.bs

<pre class=metadata>
Title: Fullscreen API Standard
Group: WHATWG
H1: Fullscreen API
Shortname: fullscreen
Status: LS
No Editor: true
Abstract: The Fullscreen API standard defines an API for elements to display themselves fullscreen.
Logo: https://resources.whatwg.org/logo-fullscreen.svg
Boilerplate: omit feedback-header, omit conformance, omit index, omit idl-index
!Participate: <a href=https://github.com/whatwg/fullscreen>GitHub whatwg/fullscreen</a> (<a href=https://github.com/whatwg/fullscreen/issues/new>file an issue</a>, <a href=https://github.com/whatwg/fullscreen/issues>open issues</a>)
!Participate: <a href=https://wiki.whatwg.org/wiki/IRC>IRC: #whatwg on Freenode</a>
!Commits: <a href=https://github.com/whatwg/fullscreen/commits>GitHub whatwg/fullscreen/commits</a>
!Commits: <a href=https://twitter.com/fullscreenapi>@fullscreenapi</a>
</pre>

<script src=https://resources.whatwg.org/file-issue.js async></script>
<script src=https://resources.whatwg.org/dfn.js defer></script>

<pre class=link-defaults>
spec:dom
    type:dfn; for:/; text:element
    type:interface; text:Document
</pre>

<pre class=anchors>
urlPrefix: https://w3c.github.io/screen-orientation/#dfn-
    type: dfn
        text: triggered by a user generated orientation change
</pre>

<pre class=biblio>
{
    "CSS": {
        "aliasOf": "CSS2"
    }
}
</pre>



<h2 id=conformance>Conformance</h2>

<p>All diagrams, examples, and notes in this specification are non-normative, as are all sections
explicitly marked non-normative. Everything else in this specification is normative.

<p>The key words "MUST", "MUST NOT", "REQUIRED", <!--"SHALL", "SHALL NOT",--> "SHOULD", "SHOULD
NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this specification are to be
interpreted as described in RFC2119. For readability, these words do not appear in all uppercase
letters in this specification. [[!RFC2119]]



<h2 id=terminology>Terminology</h2>

<p>Most terminology used in this specification is from CSS, DOM, HTML, and Web IDL. [[!CSS]]
[[!DOM]] [[!HTML]] [[!WEBIDL]]

<p>The term <dfn>context object</dfn> means the object on which the method or attribute being
discussed was called. When the <a>context object</a> is unambiguous, the term can be omitted.

<p>A <a for=/>browsing context</a> <var>A</var> is called a <dfn>descendant browsing context</dfn>
of a <a for=/>browsing context</a> <var>B</var> if and only if <var>B</var> is an
<a>ancestor browsing context</a> of <var>A</var>.



<h2 id=model>Model</h2>

<p>All <a>elements</a> have an associated <dfn>fullscreen flag</dfn>. Unless stated otherwise it is
unset.

<p>All <{iframe}> <a>elements</a> have an associated <dfn>iframe fullscreen flag</dfn>. Unless
stated otherwise it is unset.

<p>All <a for=/>documents</a> have an associated <dfn>fullscreen element</dfn>. The
<a>fullscreen element</a> is the topmost <a>element</a> in the <a for=/>document</a>'s
<a>top layer</a> whose <a>fullscreen flag</a> is set, if any, and null otherwise.

<p>To <dfn>fullscreen an <var>element</var></dfn>, set <var>element</var>'s <a>fullscreen flag</a>
and <a for="top layer">add</a> it to its <a>node document</a>'s <a>top layer</a>.

<p>To <dfn>unfullscreen an <var>element</var></dfn>, unset <var>element</var>'s
<a>fullscreen flag</a> and <a>iframe fullscreen flag</a> (if any), and <a for="top layer">remove</a>
it from its <a>node document</a>'s <a>top layer</a>.

<p>To <dfn>unfullscreen a <var>document</var></dfn>,
<a lt="unfullscreen an element">unfullscreen</a> all <a>elements</a>, within <var>document</var>'s
<a>top layer</a>, whose <a>fullscreen flag</a> is set.

<hr>

<p>To <dfn>fully exit fullscreen</dfn> a <a for=/>document</a> <var>document</var>, run these steps:

<ol>
 <li><p>If <var>document</var>'s <a>fullscreen element</a> is null, terminate these steps.

 <li><p><a lt="Unfullscreen an element">Unfullscreen elements</a> whose <a>fullscreen flag</a> is
 set, within <var>document</var>'s <a>top layer</a>, except for <var>document</var>'s
 <a>fullscreen element</a>.

 <li><p><a>Exit fullscreen</a> <var>document</var>.
</ol>

<p>Whenever the <a>removing steps</a> run with an <var>oldNode</var>, run these steps:

<ol>
 <li><p>Let <var>nodes</var> be <var>oldNode</var>'s <a>shadow-including inclusive descendants</a>
 that have their <a>fullscreen flag</a> set, in <a>shadow-including tree order</a>.

 <li>
  <p>For each <var>node</var> in <var>nodes</var>, run these substeps:

  <ol>
   <li><p>If <var>node</var> is its <a>node document</a>'s <a>fullscreen element</a>,
   <a>exit fullscreen</a> that <a for=/>document</a>.

   <li><p>Otherwise, <a lt="unfullscreen an element">unfullscreen <var>node</var></a> within its
   <a>node document</a>.
  </ol>
</ol>

<p>Whenever the <a>unloading document cleanup steps</a> run with a <var>document</var>,
<a>fully exit fullscreen</a> <var>document</var>.

<hr>

<p><dfn>Fullscreen is supported</dfn> if there is no previously-established user preference,
security risk, or platform limitation.

<p>An algorithm is <dfn>allowed to request fullscreen</dfn> if one of the following is true:

 <ul>
  <li><p>The algorithm is <a>triggered by user activation</a>.

  <li><p>The algorithm is <a>triggered by a user generated orientation change</a>.
 </ul>
<!-- cross-process -->



<h2 id=api>API</h2>

<pre class=idl>
partial interface Element {
  Promise&lt;void> requestFullscreen();
};

partial interface Document {
  [LenientSetter] readonly attribute boolean fullscreenEnabled;
  [LenientSetter] readonly attribute boolean fullscreen; // historical

  Promise&lt;void> exitFullscreen();

  attribute EventHandler onfullscreenchange;
  attribute EventHandler onfullscreenerror;
};

partial interface DocumentOrShadowRoot {
  [LenientSetter] readonly attribute Element? fullscreenElement;
};
</pre>

<dl class=domintro>
 <dt><code><var>promise</var> = <var>element</var> . {{Element/requestFullscreen()}}</code>
 <dd><p>Displays <var>element</var> fullscreen and fulfills <var>promise</var> when done.

 <dt><code><var>document</var> . {{Document/fullscreenEnabled}}</code>
 <dd><p>Returns true if <var>document</var> has the ability to display <a>elements</a> fullscreen
 and <a>fullscreen is supported</a>, or false otherwise.

 <dt><code><var>promise</var> = <var>document</var> . {{Document/exitFullscreen()}}</code>
 <dd><p>Stops <var>document</var>'s <a>fullscreen element</a> from being displayed fullscreen and
 fulfills <var>promise</var> when done.

 <dt><code><var>document</var> . {{DocumentOrShadowRoot/fullscreenElement}}</code>
 <dd><p>Returns <var>document</var>'s <a>fullscreen element</a>.

 <dt><code><var>shadowroot</var> . {{DocumentOrShadowRoot/fullscreenElement}}</code>
 <dd><p>Returns <var>shadowroot</var>'s <a>fullscreen element</a>.
</dl>

<p>A <dfn>fullscreen element ready check</dfn> for an <a>element</a> <var>element</var> returns true
if all of the following are true, and false otherwise:

<ul>
 <li><p><var>element</var> is <a>connected</a>.

 <li><p><var>element</var>'s <a>node document</a> is <a>allowed to use</a> the feature indicated by
 attribute name <code>allowfullscreen</code>.
 <!-- cross-process, recursive -->
</ul>

<p>The <dfn method for=Element><code>requestFullscreen()</code></dfn> method, when invoked, must run
these steps:

<ol>
 <li><p>Let <var>pending</var> be the <a>context object</a>.

 <li><p>Let <var>error</var> be false.

 <li><p>Let <var>promise</var> be a new promise.

 <li>
  <p>If any of the following conditions are false, then set <var>error</var> to true:

  <ul>
   <li><p><var>pending</var>'s <a for=Element>namespace</a> is the <a>HTML namespace</a> or
   <var>pending</var> is an
   <a href=https://www.w3.org/TR/SVG11/struct.html#SVGElement>SVG <code>svg</code></a> or
   <a href=https://www.w3.org/Math/draft-spec/chapter2.html#interf.toplevel>MathML <code>math</code></a>
   element. [[!SVG]] [[!MATHML]]

   <li><p>The <a>fullscreen element ready check</a> for <var>pending</var> returns true.

   <li><p><a>Fullscreen is supported</a>.

   <li><p>This algorithm is <a>allowed to request fullscreen</a>.
  </ul>

 <li><p>Return <var>promise</var>, and run the remaining steps <a>in parallel</a>.

 <li><p>If <var>error</var> is false: Resize <var>pending</var>'s
 <a>top-level browsing context</a>'s <a>active document</a>'s viewport's dimensions to match the
 dimensions of the screen of the output device. Optionally display a message how the end user can
 revert this.
 <!-- cross-process -->

 <li>
  <p>As part of the next <a>animation frame task</a>, run these substeps:

  <ol>
   <li><p>If either <var>error</var> is true or the <a>fullscreen element ready check</a> for
   <var>pending</var> returns false, <a>fire an event</a> named <code>fullscreenerror</code> on
   <var>pending</var>'s <a>node document</a>, reject <var>promise</var> with a
   <code>TypeError</code> exception, and terminate these steps.
   <!-- cross-process; check is only needed on pending as it is recursive already -->

   <li><p>Let <var>fullscreenElements</var> be an ordered set initially consisting of
   <var>pending</var>.

   <li><p>While the first element in <var>fullscreenElements</var> is in a
   <a>nested browsing context</a>, prepend its <a>browsing context container</a> to
   <var>fullscreenElements</var>.
   <!-- cross-process -->

   <li><p>Let <var>eventDocs</var> be an empty list.

   <li>
    <p>For each <var>element</var> in <var>fullscreenElements</var>, in order, run these
    subsubsteps:

    <ol>
     <li><p>Let <var>doc</var> be <var>element</var>'s <a>node document</a>.

     <li>
      <p>If <var>element</var> is <var>doc</var>'s <a>fullscreen element</a>, terminate these
      subsubsteps.

      <p class=note>No need to notify observers when nothing has changed.

     <li><p>Otherwise, append <var>doc</var> to <var>eventDocs</var>.

     <li><p>If <var>element</var> is <var>pending</var> and <var>pending</var> is an <{iframe}>
     <a>element</a>, then set <var>element</var>'s <a>iframe fullscreen flag</a>.

     <li><p><a lt="Fullscreen an element">Fullscreen <var>element</var></a> within <var>doc</var>.
    </ol>

   <li><p>For each <var>doc</var> in <var>eventDocs</var>, in order, <a>fire an event</a> named
   <code>fullscreenchange</code> on <var>doc</var>.

   <li><p>Fulfill <var>promise</var> with undefined.
  </ol>

  <p class=XXX><dfn>Animation frame task</dfn> is not really defined yet, including relative order
  within that task, see <a href=https://www.w3.org/Bugs/Public/show_bug.cgi?id=26440>bug 26440</a>.

  <p class=note>Implementations with out-of-process <a for=/>browsing contexts</a> are left as an
  exercise to the reader. Input welcome on potential improvements.
</ol>

<p>The <dfn attribute for=Document><code>fullscreenEnabled</code></dfn> attribute's getter must
return true if the <a>context object</a> is <a>allowed to use</a> the feature indicated by attribute
name <code>allowfullscreen</code> and <a>fullscreen is supported</a>, and false otherwise.

<p>The <dfn attribute for=Document><code>fullscreen</code></dfn> attribute's getter must return
false if <a>context object</a>'s <a>fullscreen element</a> is null, and true otherwise.

<p class=note>Use the {{DocumentOrShadowRoot/fullscreenElement}} attribute instead.

<p>The
<dfn attribute for=DocumentOrShadowRoot id=dom-document-fullscreenelement><code>fullscreenElement</code></dfn>
attribute's getter must run these steps:

<ol>
 <li><p>If the <a>context object</a> is a <a for=/>shadow root</a> and its
 <a for=DocumentFragment>host</a> is not <a>connected</a>, then return null.</li>

 <li><p>Let <var>candidate</var> be the result of <a>retargeting</a> <a>fullscreen element</a>
 against the <a>context object</a>.

 <li><p>If <var>candidate</var> and the <a>context object</a> are in the same <a>tree</a>, then
 return <var>candidate</var>.

 <li><p>Return null.
</ol>

<p>To <dfn>collect documents to unfullscreen</dfn> given <var>doc</var>, run these steps:

<ol>
 <li><p>If <var>doc</var>'s <a>top layer</a> consists of more than a single <a>element</a> that has
 its <a>fullscreen flag</a> set, return the empty set.

 <li><p>Let <var>docs</var> be an ordered set consisting of <var>doc</var>.

 <li><p>While <var>docs</var>'s last <a for=/>document</a> has a <a>browsing context container</a>
 whose <a>node document</a>'s <a>top layer</a> consists of a single <a>element</a> that has its
 <a>fullscreen flag</a> set and does not have its <a>iframe fullscreen flag</a> set (if any), append
 that <a>node document</a> to <var>docs</var>.

 <li><p>Return <var>docs</var>.
</ol>

<p>To <dfn>exit fullscreen</dfn> a <a for=/>document</a> <var>doc</var>, run these steps:

<ol>
 <li><p>Let <var>promise</var> be a new promise.

 <li><p>If <var>doc</var>'s <a>fullscreen element</a> is null, reject <var>promise</var> with a
 <code>TypeError</code> exception, and return <var>promise</var>.

 <li><p>Let <var>resize</var> be false.

 <li><p>Let <var>docs</var> be the result of
 <a lt="collect documents to unfullscreen">collecting documents to unfullscreen</a> given
 <var>doc</var>.
 <!-- cross-process -->

 <li><p>Let <var>topLevelDoc</var> be <var>doc</var>'s <a>top-level browsing context</a>'s
 <a>active document</a>.
 <!-- cross-process -->

 <li><p>If <var>topLevelDoc</var> is in <var>docs</var>, then set <var>resize</var> to true.

 <li><p>Return <var>promise</var>, and run the remaining steps <a>in parallel</a>.

 <li><p>If <var>resize</var> is true, resize <var>topLevelDoc</var>'s viewport to its "normal"
 dimensions.

 <li>
  <p>As part of the next <a>animation frame task</a>, run these substeps:

  <ol>

   <li><p>Let <var>exitDocs</var> be the result of
   <a lt="collect documents to unfullscreen">collecting documents to unfullscreen</a> given
   <var>doc</var>.
   <!-- cross-process -->

   <li><p>If <var>resize</var> is true and <var>topLevelDoc</var> is not in <var>exitDocs</var>,
   <a>fully exit fullscreen</a> <var>topLevelDoc</var>, reject <var>promise</var> with a
   <code>TypeError</code> exception, and terminate these steps.

   <li><p>If <var>exitDocs</var> is the empty set, append <var>doc</var> to <var>exitDocs</var>.

   <li><p>If <var>exitDocs</var>'s last <a for=/>document</a> has a
   <a>browsing context container</a>, append that <a>browsing context container</a>'s
   <a>node document</a> to <var>exitDocs</var>.
   <!-- cross-process -->

   <li><p>Let <var>descendantDocs</var> be an ordered set consisting of <var>doc</var>'s
   <a>descendant browsing contexts</a>' <a>active documents</a> whose <a>fullscreen element</a> is
   non-null, if any, in <em>reverse</em> <a>tree order</a>.
   <!-- cross-process -->

   <li><p>For each <var>descendantDoc</var> in <var>descendantDocs</var>, in order,
   <a lt="unfullscreen a document">unfullscreen <var>descendantDoc</var></a>.
   <!-- cross-process -->

   <li><p>For each <var>exitDoc</var> in <var>exitDocs</var>, in order,
   <a lt="unfullscreen an element">unfullscreen</a> <var>exitDoc</var>'s <a>fullscreen element</a>.

   <li><p>For each <var>descendantDoc</var> in <var>descendantDocs</var>, in order,
   <a>fire an event</a> named <code>fullscreenchange</code> on <var>descendantDoc</var>.
   <!-- cross-process -->

   <li><p>For each <var>exitDoc</var> in <var>exitDocs</var>, in order, <a>fire an event</a> named
   <code>fullscreenchange</code> on <var>exitDoc</var>.
   <!-- cross-process -->

   <li><p>Fulfill <var>promise</var> with undefined.
  </ol>

  <p class=note>This results in events being fired from the innermost to the outermost document.
</ol>

<p>The <dfn method for=Document><code>exitFullscreen()</code></dfn> method, when invoked, must
return the result of running <a>exit fullscreen</a> on the <a>context object</a>.

<hr>

<p>The following are the <a>event handlers</a> (and their corresponding
<a>event handler event types</a>) that must be supported on <a for=/>documents</a> as attributes:

<table>
 <thead>
	<tr>
	 <th><a lt="event handlers">event handler</a>
	 <th><a>event handler event type</a>
 <tbody>
	<tr>
	 <td><dfn attribute for=Document id=handler-document-onfullscreenchange><code>onfullscreenchange</code></dfn>
	 <td><code>fullscreenchange</code>
	<tr>
	 <td><dfn attribute for=Document id=handler-document-onfullscreenerror><code>onfullscreenerror</code></dfn>
	 <td><code>fullscreenerror</code>
</table>



<h2 id=ui>UI</h2>

<p>User agents are encouraged to implement native media fullscreen controls in terms of
{{Element/requestFullscreen()}} and {{Document/exitFullscreen()}}.

<p>If the end user instructs the user agent to end a fullscreen session initiated via
{{Element/requestFullscreen()}}, <a>fully exit fullscreen</a> the
<a>top-level browsing context</a>'s <a>active document</a>.



<h2 id=rendering>Rendering</h2>

<p>This section is to be interpreted equivalently to the Rendering section of HTML. [[!HTML]]

<p class=XXX>Long term CSS will define the <a>top layer</a> concept and its associated
<a><code>::backdrop</code></a> pseudo-element as part of CSS' stacking context model. Patching CSS
as done here is sketchy as hell.


<h3 id=new-stacking-layer>New stacking layer</h3>

<p>This specification introduces a new stacking layer to the
<a href=https://www.w3.org/TR/CSS2/zindex.html>Elaborate description of Stacking Contexts</a> of CSS
2.1. It is called the <dfn export>top layer</dfn>, comes after step 10 in the painting order, and is
therefore rendered closest to the user within a viewport. Each <a for=/>document</a> has one
associated viewport and therefore also one <a>top layer</a>. [[!CSS]]

<p class=note>The terminology used in this and following subsection attempts to match CSS 2.1
Appendix E.

<p>The <a>top layer</a> consists of an ordered set of elements, rendered in the order they have been
added to the set. The last element added is rendered closest to the user.

<p class=note>The <code>z-index</code> property has no effect in the <a>top layer</a>.

<p>Each element and <a><code>::backdrop</code></a> pseudo-element in a <a>top layer</a> has the
following characteristics:

<ul>
 <li><p>It generates a new stacking context.

 <li><p>Its parent stacking context is the root stacking context.

 <li><p>If it consists of multiple layout boxes, the first box is used.
 <!-- https://www.w3.org/Bugs/Public/show_bug.cgi?id=24523 -->

 <li>
  <p>It is rendered as an atomic unit as if it were a sibling of its <a for=tree>root</a>.

  <p class=note><a for=tree>Ancestor</a> elements with overflow, opacity, masks, etc. cannot affect
  it.

 <li><p>If its <code>position</code> property computes to <code>fixed</code>, its containing block
 is the viewport, and the initial containing block otherwise.

 <li><p>If it is an element, it and its <a><code>::backdrop</code></a> pseudo-element are not
 rendered if its <a>shadow-including inclusive ancestor</a> has the <code>display</code> property
 set to <code>none</code>.

 <li><p>If its specified <code>display</code> property is <code>contents</code>, it computes to
 <code>block</code>.

 <li><p>If its specified <code>position</code> property is not <code>absolute</code> or
 <code>fixed</code>, it computes to <code>absolute</code>.

 <li><p>Its outline, if any, is to be rendered before step 10 in the painting order.

 <li><p>Unless overridden by another specification, its static position for <code>left</code>,
 <code>right</code>, and <code>top</code> is zero.
</ul>

<p>To <dfn export for="top layer">add</dfn> an <var>element</var> to a <var>top layer</var>, add, or
move if already present, <var>element</var> on top of <var>top layer</var>.

<p>To <dfn export for="top layer">remove</dfn> an <var>element</var> from a <var>top layer</var>,
remove <var>element</var> from <var>top layer</var>.


<h3 id=::backdrop-pseudo-element><code>::backdrop</code> pseudo-element</h3>

<p>Each element in a <a>top layer</a> has a
<dfn id=css-pe-backdrop selector><code>::backdrop</code></dfn> pseudo-element. This pseudo-element
is a box rendered immediately below the element (and above the element before the element in the
set, if any), within the same <a>top layer</a>.

<p class=note>The <a><code>::backdrop</code></a> pseudo-element can be used to create a backdrop
that hides the underlying document for an element in a <a>top layer</a> (such as an element that is
displayed fullscreen).

<p>It does not inherit from any element and is not inherited from. No restrictions are made on what
properties apply to this pseudo-element either.

<!-- That this is not in a more normative prose is because CSS should have hooks for this stuff
     which make it normative. -->


<h3 id=:fullscreen-pseudo-class><code>:fullscreen</code> pseudo-class</h3>

<p>The <dfn id=css-pc-fullscreen selector><code>:fullscreen</code></dfn> pseudo-class must match any
<a>element</a> <var>element</var> for which one of the following conditions is true:

<ul>
 <li><p><var>element</var>'s <a>fullscreen flag</a> is set.

 <li><p><var>element</var> is a <a>shadow host</a> and the result of <a>retargeting</a> its
 <a>node document</a>'s <a>fullscreen element</a> against <var>element</var> is <var>element</var>.
</ul>

<p class="note no-backref">This makes it different from the
{{DocumentOrShadowRoot/fullscreenElement}} API, which returns the topmost <a>fullscreen element</a>.

<h3 id=user-agent-level-style-sheet-defaults>User-agent level style sheet defaults</h3>
<!-- HTML's "The CSS user agent style sheet and presentational hints" section uses this term -->

<pre class=css>
@namespace "http://www.w3.org/1999/xhtml";

*|*:not(:root):fullscreen {
  position:fixed !important;
  top:0 !important; right:0 !important; bottom:0 !important; left:0 !important;
  margin:0 !important;
  box-sizing:border-box !important;
  min-width:0 !important;
  max-width:none !important;
  min-height:0 !important;
  max-height:none !important;
  width:100% !important;
  height:100% !important;
  transform:none !important;

  /* intentionally not !important */
  object-fit:contain;
}

iframe:fullscreen {
  border:none !important;
  padding:0 !important;
}

::backdrop {
  position:fixed;
  top:0; right:0; bottom:0; left:0;
}

*|*:not(:root):fullscreen::backdrop {
  background:black;
}
</pre>



<h2 id=security-and-privacy-considerations>Security and Privacy Considerations</h2>

<p>User agents should ensure, e.g. by means of an overlay, that the end user is aware something is
displayed fullscreen. User agents should provide a means of exiting fullscreen that always works and
advertise this to the user. This is to prevent a site from spoofing the end user by recreating the
user agent or even operating system environment when fullscreen. See also the definition of
{{Element/requestFullscreen()}}.

<p>To enable content in a <a>nested browsing context</a> to go fullscreen, it needs to be
specifically allowed via the <code>allowfullscreen</code> attribute of the HTML <{iframe}> element.
This prevents e.g. content from third parties to go fullscreen without explicit permission.



<div data-fill-with=references></div>



<h2 id=acknowledgments class=no-num>Acknowledgments</h2>

<p>Many thanks to Robert O'Callahan for designing the initial model and being awesome.
<!-- https://wiki.mozilla.org/Gecko:FullScreenAPI -->

<p>Thanks to
Andy Earnshaw,
Chris Pearce,
Darin Fisher,
<i>fantasai</i>,
Giuseppe Pascale,
Glenn Maynard,
Ian Hickson,
Ignacio Solla,
João Eiras,
Josh Soref,
Matt Falkenhagen,
Mihai Balan,
Mounir Lamouri,
Øyvind Stenhaug,
Pat Ladd,
Philip Jägenstedt,
Rafał Chłodnicki,
Riff Jiang,
Rune Lillesveen,
Sigbjørn Vik,
Simon Pieters,
Tab Atkins,
Takayoshi Kochi,
Theresa O'Connor,
Vincent Scheib, and
Xidorn Quan
for also being awesome.

<p>This standard is written by <a lang=nl href=https://annevankesteren.nl/>Anne van Kesteren</a>
(<a href=https://www.mozilla.org/>Mozilla</a>,
<a href=mailto:annevk@annevk.nl>annevk@annevk.nl</a>).
<a lang=tr href=http://tantek.com/>Tantek Çelik</a>
(<a class="p-org org h-org h-card" href=https://www.mozilla.org/>Mozilla</a>,
<a href=mailto:tantek@cs.stanford.edu>tantek@cs.stanford.edu</a>) sorted out legal hassles.

<p>Per <a rel=license href=https://creativecommons.org/publicdomain/zero/1.0/>CC0</a>, to the extent
possible under law, the editor has waived all copyright and related or neighboring rights to this
work.