@@ -689,7 +689,9 @@
<li><a href=#killing-scripts><span class=secno>5.5.3.4 </span>Killing scripts</a></ol></li>
<li><a href=#event-loops><span class=secno>5.5.4 </span>Event loops</a>
<ol>
<li><a href=#generic-task-sources><span class=secno>5.5.4.1 </span>Generic task sources</a></ol></li>
<li><a href=#definitions-1><span class=secno>5.5.4.1 </span>Definitions</a></li>
<li><a href=#processing-model-2><span class=secno>5.5.4.2 </span>Processing model</a></li>
<li><a href=#generic-task-sources><span class=secno>5.5.4.3 </span>Generic task sources</a></ol></li>
<li><a href=#javascript-protocol><span class=secno>5.5.5 </span>The <code title="">javascript:</code> protocol</a></li>
<li><a href=#events><span class=secno>5.5.6 </span>Events</a>
<ol>
@@ -828,7 +830,7 @@
<li><a href=#undo><span class=secno>6.10 </span>Undo history</a>
<ol>
<li><a href=#introduction-4><span class=secno>6.10.1 </span>Introduction</a></li>
<li><a href=#definitions-1 ><span class=secno>6.10.2 </span>Definitions</a></li>
<li><a href=#definitions-2 ><span class=secno>6.10.2 </span>Definitions</a></li>
<li><a href=#the-undomanager-interface><span class=secno>6.10.3 </span>The <code>UndoManager</code> interface</a></li>
<li><a href=#undo:-moving-back-in-the-undo-transaction-history><span class=secno>6.10.4 </span>Undo: moving back in the undo transaction history</a></li>
<li><a href=#redo:-moving-forward-in-the-undo-transaction-history><span class=secno>6.10.5 </span>Redo: moving forward in the undo transaction history</a></li>
@@ -1400,14 +1402,6 @@
imply a visual medium; they must be considered to apply to other
media in equivalent ways.</p>
<p class=impl>Some of the algorithms in this specification, for
historical reasons, require the user agent to <dfn id=pause>pause</dfn> until
some condition has been met. While a user agent is paused, it must
ensure that no scripts execute (e.g. no event handlers, no timers,
etc). User agents should remain responsive to user input while
paused, however, albeit without letting the user interact with Web
pages where that would involve invoking any <a href=#concept-script title=concept-script>script</a>.</p>
<h4 id=xml><span class=secno>2.1.1 </span>XML</h4>
<h4 id=event-loops><span class=secno>5.5.4 </span>Event loops</h4>
<h5 id=definitions-1><span class=secno>5.5.4.1 </span>Definitions</h5>
<p>To coordinate events, user interaction, scripts, rendering,
networking, and so forth, user agents must use <dfn id=event-loop title="event
loop">event loops</dfn> as described in this section.</p>
processing events from any one <a href=#task-source>task source</a> out of
order.</p>
<p>A user agent is required to have one <dfn id=storage-mutex>storage
mutex</dfn>. This mutex is used to control access to shared state
like cookies. At any one point, the <a href=#storage-mutex>storage mutex</a> is
either free, or owned by a particular <a href=#event-loop>event loop</a>.</p>
<h5 id=processing-model-2><span class=secno>5.5.4.2 </span>Processing model</h5>
<p>An <a href=#event-loop>event loop</a> must continually run through the
following steps for as long as it exists:</p>
<ol><li><p>Run the oldest task on one of the <a href=#event-loop>event loop</a>'s
<a href=#task-queue title="task queue">task queues</a>, ignoring tasks whose
associated <code>Document</code>s are not <a href=#fully-active>fully
active</a>. The user agent may pick any <a href=#task-queue>task
queue</a>.</li>
<ol><li><p>Run the oldest <a href=#concept-task title=concept-task>task</a> on one
of the <a href=#event-loop>event loop</a>'s <a href=#task-queue title="task queue">task
queues</a>, ignoring tasks whose associated
<code>Document</code>s are not <a href=#fully-active>fully active</a>. The user
agent may pick any <a href=#task-queue>task queue</a>.</li>
<li><p>If the <a href=#storage-mutex>storage mutex</a> is now owned by the
<a href=#event-loop>event loop</a>, release it so that it is once again
free.</p>
<li><p>Remove that task from its <a href=#task-queue>task queue</a>.</li>
<li><p>Return to the first step of the <a href=#event-loop>event
loop</a>.</li>
</ol><hr><p class=impl>Some of the algorithms in this specification, for
historical reasons, require the user agent to <dfn id=pause>pause</dfn> while
running a <a href=#concept-task title=concept-task>task</a> until some
condition has been met. While a user agent has a paused <a href=#concept-task title=concept-task>task</a>, the corresponding <a href=#event-loop>event
loop</a> must not run further <a href=#concept-task title=concept-task>tasks</a>, and any script in the currently
running <a href=#concept-task title=concept-task>task</a> must block. User
agents should remain responsive to user input while paused, however,
albeit in a reduced capacity since the <a href=#event-loop>event loop</a> will
not be doing anything.</p>
<hr><p>When a user agent is to <dfn id=obtain-the-storage-mutex>obtain the storage mutex</dfn> as
part of running a <a href=#concept-task title=concept-task>task</a>, it must
run through the following steps:</p>
<ol><li><p>If the <a href=#storage-mutex>storage mutex</a> is already owned by this
<a href=#concept-task title=concept-task>task</a>'s <a href=#event-loop>event loop</a>,
then abort these steps.</li>
<li><p>Otherwise, <a href=#pause>pause</a> until the <a href=#storage-mutex>storage
mutex</a> can be taken by the <a href=#event-loop>event loop</a>.</li>
<li><p>Take ownership of the <a href=#storage-mutex>storage mutex</a>.</li>
</ol></div>
<div class=impl>
<h5 id=generic-task-sources><span class=secno>5.5.4.1 </span>Generic task sources</h5>
<h5 id=generic-task-sources><span class=secno>5.5.4.3 </span>Generic task sources</h5>
<p>The following <a href=#task-source title="task source">task sources</a> are
used by a number of mostly unrelated features in this and other
<div class=impl>
<h4 id=definitions-1 ><span class=secno>6.10.2 </span>Definitions</h4>
<h4 id=definitions-2 ><span class=secno>6.10.2 </span>Definitions</h4>
<p>The user agent must associate an <dfn id=undo-transaction-history>undo transaction
history</dfn> with each <code><a href=#htmldocument>HTMLDocument</a></code> object.</p>
