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  <title>HTML5 differences from HTML4</title>

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     Editor's checklist for stuff to fix for publication:

       * Previous Versions links
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   <h1 id=html5-diff>HTML5 differences from HTML4</h1>

   <h2 class="no-num no-toc" id=w3c-doctype>W3C Working Draft 25 May 2011</h2>

   <dl>
    <dt>This Version:

    <dd><a
     href="http://www.w3.org/TR/2011/WD-html5-diff-20110525/">http://www.w3.org/TR/2011/WD-html5-diff-20110525/</a>

    <dt>Latest Published Version:

    <dd><a
     href="http://www.w3.org/TR/html5-diff/">http://www.w3.org/TR/html5-diff/</a>

    <dt>Latest Editor's Draft:

    <dd><a
     href="http://dev.w3.org/html5/html4-differences/">http://dev.w3.org/html5/html4-differences/</a>

    <dt>Previous Versions:

    <dd><a
     href="http://www.w3.org/TR/2011/WD-html5-diff-20110405/">http://www.w3.org/TR/2011/WD-html5-diff-20110405/</a>

    <dd><a
     href="http://www.w3.org/TR/2011/WD-html5-diff-20110113/">http://www.w3.org/TR/2011/WD-html5-diff-20110113/</a>

    <dd><a
     href="http://www.w3.org/TR/2010/WD-html5-diff-20101019/">http://www.w3.org/TR/2010/WD-html5-diff-20101019/</a>

    <dd><a
     href="http://www.w3.org/TR/2010/WD-html5-diff-20100624/">http://www.w3.org/TR/2010/WD-html5-diff-20100624/</a>

    <dd><a
     href="http://www.w3.org/TR/2010/WD-html5-diff-20100304/">http://www.w3.org/TR/2010/WD-html5-diff-20100304/</a>

    <dd><a
     href="http://www.w3.org/TR/2009/WD-html5-diff-20090825/">http://www.w3.org/TR/2009/WD-html5-diff-20090825/</a>

    <dd><a
     href="http://www.w3.org/TR/2009/WD-html5-diff-20090423/">http://www.w3.org/TR/2009/WD-html5-diff-20090423/</a>

    <dd><a
     href="http://www.w3.org/TR/2009/WD-html5-diff-20090212/">http://www.w3.org/TR/2009/WD-html5-diff-20090212/</a>

    <dd><a
     href="http://www.w3.org/TR/2008/WD-html5-diff-20080610/">http://www.w3.org/TR/2008/WD-html5-diff-20080610/</a>

    <dd><a
     href="http://www.w3.org/TR/2008/WD-html5-diff-20080122/">http://www.w3.org/TR/2008/WD-html5-diff-20080122/</a>

    <dt>Editors:

    <dd><a href="http://annevankesteren.nl/">Anne van Kesteren</a> (<a
     href="http://www.opera.com/">Opera Software ASA</a>) &lt;<a
     href="mailto:annevk@opera.com">annevk@opera.com</a>>

    <dd>Simon Pieters (<a href="http://www.opera.com/">Opera Software
     ASA</a>) &lt;<a href="mailto:simonp@opera.com">simonp@opera.com</a>>
   </dl>

   <p class=copyright><a
    href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a>
    &copy; 2011 <a href="http://www.w3.org/"><abbr title="World Wide Web
    Consortium">W3C</abbr></a><sup>&reg;</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>), All Rights Reserved. W3C <a
    href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
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    href="http://www.w3.org/Consortium/Legal/copyright-documents">document
    use</a> rules apply.</p>
  </div>

  <hr>

  <h2 class="no-num no-toc" id=abstract>Abstract</h2>

  <p>HTML5 defines the fifth major revision of the core language of the World
   Wide Web, HTML. "HTML5 differences from HTML4" describes the differences
   between HTML4 and HTML5 and provides some of the rationale for the
   changes. This document may not provide accurate information as the HTML5
   specification is still actively in development. When in doubt, always
   check the HTML5 specification itself. [<cite><a
   href="#ref-html5">HTML5</a></cite>]

  <h2 class="no-num no-toc" id=sotd>Status of this Document</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 W3C publications and the latest revision of this technical report
   can be found in the <a href="http://www.w3.org/TR/">W3C technical reports
   index</a> at http://www.w3.org/TR/.</em>

  <p>This is the 25 May 2011 W3C Working Draft produced by the <a
   href="http://www.w3.org/html/wg/">HTML Working Group</a>, part of the <a
   href="http://www.w3.org/MarkUp/Activity">HTML Activity</a>. The Working
   Group intends to publish this document as a <a
   href="http://www.w3.org/2005/10/Process-20051014/#WGNote">Working Group
   Note</a> to accompany the <a href="http://www.w3.org/TR/html5/">HTML5
   specification</a>. The appropriate forum for comments is <a
   href="http://www.w3.org/Bugs/Public/enter_bug.cgi?product=HTML%20WG&amp;component=HTML5%20differences%20from%20HTML4%20%28editor:%20Anne%20van%20Kesteren%29">W3C
   Bugzilla</a>.
   Alternatively, submit comments to <a href="mailto:public-html-comments@w3.org@w3.org">public-html-comments@w3.org</a>
   (<a href="mailto:public-html-comments-request@w3.org?subject=subscribe">subscribe</a>,
    <a href="http://lists.w3.org/Archives/Public/public-html-comments/">archives</a>)
   and arrangements will be made to transpose the comments to the bug database.

  <p>Publication as a Working Draft does not imply endorsement by the W3C
   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>This document was produced by a group operating under the <a
   href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
   2004 W3C Patent Policy</a>. W3C maintains a <a
   href="http://www.w3.org/2004/01/pp-impl/40318/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 W3C Patent Policy</a>.

  <h2 class="no-num no-toc" id=toc>Table of Contents</h2>
  <!--begin-toc-->

  <ul class=toc>
   <li><a href="#introduction"><span class=secno>1. </span>Introduction</a>
    <ul class=toc>
     <li><a href="#open-issues"><span class=secno>1.1. </span>Open Issues</a>


     <li><a href="#backwards-compatible"><span class=secno>1.2.
      </span>Backwards Compatible</a>

     <li><a href="#development-model"><span class=secno>1.3.
      </span>Development Model</a>
    </ul>

   <li><a href="#syntax"><span class=secno>2. </span>Syntax</a>
    <ul class=toc>
     <li><a href="#character-encoding"><span class=secno>2.1.
      </span>Character Encoding</a>

     <li><a href="#doctype"><span class=secno>2.2. </span>The DOCTYPE</a>

     <li><a href="#mathml-svg"><span class=secno>2.3. </span>MathML and
      SVG</a>

     <li><a href="#syntax-misc"><span class=secno>2.4.
      </span>Miscellaneous</a>
    </ul>

   <li><a href="#language"><span class=secno>3. </span>Language</a>
    <ul class=toc>
     <li><a href="#new-elements"><span class=secno>3.1. </span>New
      Elements</a>

     <li><a href="#new-attributes"><span class=secno>3.2. </span>New
      Attributes</a>

     <li><a href="#changed-elements"><span class=secno>3.3. </span>Changed
      Elements</a>

     <li><a href="#changed-attributes"><span class=secno>3.4. </span>Changed
      Attributes</a>

     <li><a href="#absent-elements"><span class=secno>3.5. </span>Absent
      Elements</a>

     <li><a href="#absent-attributes"><span class=secno>3.6. </span>Absent
      Attributes</a>
    </ul>

   <li><a href="#apis"><span class=secno>4. </span>APIs</a>
    <ul class=toc>
     <li><a href="#htmldocument-extensions"><span class=secno>4.1.
      </span>Extensions to <code>HTMLDocument</code></a>

     <li><a href="#htmlelement-extensions"><span class=secno>4.2.
      </span>Extensions to <code>HTMLElement</code></a>
    </ul>

   <li><a href="#changelog"><span class=secno>5. </span>HTML5 Changelogs</a>
    <ul class=toc>
     <li><a href="#changes-2011-04-05"><span class=secno>5.1. </span>Changes
      since 5 April 2011</a>

     <li><a href="#changes-2011-01-13"><span class=secno>5.2. </span>Changes
      from 13 January 2011 to 5 April 2011</a>

     <li><a href="#changes-2010-10-19"><span class=secno>5.3. </span>Changes
      from 19 October 2010 to 13 January 2011</a>

     <li><a href="#changes-2010-06-24"><span class=secno>5.4. </span>Changes
      from 24 June 2010 to 19 October 2010</a>

     <li><a href="#changes-2010-03-04"><span class=secno>5.5. </span>Changes
      from 4 March 2010 to 24 June 2010</a>

     <li><a href="#changes-2009-08-25"><span class=secno>5.6. </span>Changes
      from 25 August 2009 to 4 March 2010</a>

     <li><a href="#changes-2009-04-23"><span class=secno>5.7. </span>Changes
      from 23 April 2009 to 25 August 2009</a>

     <li><a href="#changes-2009-02-12"><span class=secno>5.8. </span>Changes
      from 12 February 2009 to 23 April 2009</a>

     <li><a href="#changes-2008-06-10"><span class=secno>5.9. </span>Changes
      from 10 June 2008 to 12 February 2009</a>

     <li><a href="#changes-2008-01-22"><span class=secno>5.10. </span>Changes
      from 22 January 2008 to 10 June 2008</a>
    </ul>

   <li class=no-num><a href="#acknowledgments">Acknowledgments</a>

   <li class=no-num><a href="#references">References</a>
  </ul>
  <!--end-toc-->

  <h2 id=introduction><span class=secno>1. </span>Introduction</h2>

  <p>HTML has been in continuous evolution since it was introduced to the
   Internet in the early 1990s. Some features were introduced in
   specifications; others were introduced in software releases. In some
   respects, implementations and author practices have converged with each
   other and with specifications and standards, but in other ways, they
   continue to diverge.

  <p>HTML4 became a W3C Recommendation in 1997. While it continues to serve
   as a rough guide to many of the core features of HTML, it does not provide
   enough information to build implementations that interoperate with each
   other and, more importantly, with a critical mass of deployed content. The
   same goes for XHTML1, which defines an XML serialization for HTML4, and
   DOM Level 2 HTML, which defines JavaScript APIs for both HTML and XHTML.
   HTML5 will replace these documents. [<cite><a
   href="#ref-dom2html">DOM2HTML</a></cite>] [<cite><a
   href="#ref-html4">HTML4</a></cite>] [<cite><a
   href="#ref-xhtml1">XHTML1</a></cite>]

  <p>The HTML5 draft reflects an effort, started in 2004, to study
   contemporary HTML implementations and deployed content. The draft:

  <ol>
   <li>Defines a single language called HTML5 which can be written in HTML
    syntax and in XML syntax.

   <li>Defines detailed processing models to foster interoperable
    implementations.

   <li>Improves markup for documents.

   <li>Introduces markup and APIs for emerging idioms, such as Web
    applications.
  </ol>

  <h3 id=open-issues><span class=secno>1.1. </span>Open Issues</h3>

  <p><strong>HTML5 is still a draft.</strong> The contents of HTML5, as well
   as the contents of this document which depend on HTML5, are still being
   discussed on the HTML Working Group and WHATWG mailing lists. The open
   issues are linked from the HTML5 draft.

  <h3 id=backwards-compatible><span class=secno>1.2. </span>Backwards
   Compatible</h3>

  <p>HTML5 is defined in a way that it is backwards compatible with the way
   user agents handle deployed content. To keep the authoring language
   relatively simple for authors several elements and attributes are not
   included as outlined in the other sections of this document, such as
   presentational elements that are better dealt with using CSS.

  <p>User agents, however, will always have to support these older elements
   and attributes and this is why the HTML5 specification clearly separates
   requirements for authors and user agents. For instance, this means that
   authors cannot use the <code>isindex</code> or the <code>plaintext</code>
   element, but user agents are required to support them in a way that is
   compatible with how these elements need to behave for compatibility with
   deployed content.

  <p>Since HTML5 has separate conformance requirements for authors and user
   agents there is no longer a need for marking features "deprecated".

  <h3 id=development-model><span class=secno>1.3. </span>Development Model</h3>

  <p>The HTML5 specification will not be considered finished before there are
   at least two complete implementations of the specification. A test suite
   will be used to measure completeness of the implementations. This approach
   differs from previous versions of HTML, where the final specification
   would typically be approved by a committee before being actually
   implemented. The goal of this change is to ensure that the specification
   is implementable, and usable by authors once it is finished.

  <h2 id=syntax><span class=secno>2. </span>Syntax</h2>

  <p>HTML5 defines an HTML syntax that is compatible with HTML4 and XHTML1
   documents published on the Web, but is not compatible with the more
   esoteric SGML features of HTML4, such as <a
   href="http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.6">processing
   instructions</a> and <a
   href="http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.7">shorthand
   markup</a> as these are not supported by most user agents. Documents using
   the HTML syntax are almost always served with the <code>text/html</code>
   media type.

  <p>HTML5 also defines detailed parsing rules (including "error handling")
   for this syntax which are largely compatible with popular implementations.
   User agents must use these rules for resources that have the
   <code>text/html</code> media type. Here is an example document that
   conforms to the HTML syntax:

  <pre><code>&lt;!doctype html>
&lt;html>
  &lt;head>
    &lt;meta charset="UTF-8">
    &lt;title>Example document&lt;/title>
  &lt;/head>
  &lt;body>
    &lt;p>Example paragraph&lt;/p>
  &lt;/body>
&lt;/html></code></pre>

  <p>HTML5 also defines a <code>text/html-sandboxed</code> media type for
   documents using the HTML syntax. This can be used when hosting untrusted
   content.

  <p>The other syntax that can be used for HTML5 is XML. This syntax is
   compatible with XHTML1 documents and implementations. Documents using this
   syntax need to be served with an XML media type and elements need to be
   put in the <code>http://www.w3.org/1999/xhtml</code> namespace following
   the rules set forth by the XML specifications. [<cite><a
   href="#ref-xml">XML</a></cite>]

  <p>Below is an example document that conforms to the XML syntax of HTML5.
   Note that XML documents must be served with an XML media type such as
   <code>application/xhtml+xml</code> or <code>application/xml</code>.

  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?>
&lt;html xmlns="http://www.w3.org/1999/xhtml">
  &lt;head>
    &lt;title>Example document&lt;/title>
  &lt;/head>
  &lt;body>
    &lt;p>Example paragraph&lt;/p>
  &lt;/body>
&lt;/html></code></pre>

  <h3 id=character-encoding><span class=secno>2.1. </span>Character Encoding</h3>

  <p>For the HTML syntax of HTML5, authors have three means of setting the
   character encoding:

  <ul>
   <li>At the transport level. By using the HTTP <code>Content-Type</code>
    header for instance.

   <li>Using a Unicode Byte Order Mark (BOM) character at the start of the
    file. This character provides a signature for the encoding used.

   <li>Using a <code>meta</code> element with a <code>charset</code>
    attribute that specifies the encoding within the first 1024 bytes of the
    document. E.g. <code>&lt;meta charset="UTF-8"></code> could be used to
    specify the UTF-8 encoding. This replaces the need for <code>&lt;meta
    http-equiv="Content-Type" content="text/html; charset=UTF-8"></code>
    although that syntax is still allowed.
  </ul>

  <p>For the XML syntax, authors have to use the rules as set forth in the
   XML specifications to set the character encoding.

  <h3 id=doctype><span class=secno>2.2. </span>The DOCTYPE</h3>

  <p>The HTML syntax of HTML5 requires a DOCTYPE to be specified to ensure
   that the browser renders the page in standards mode. The DOCTYPE has no
   other purpose and is therefore optional for XML. Documents with an XML
   media type are always handled in standards mode. [<cite><a
   href="#ref-doctype">DOCTYPE</a></cite>]

  <p>The DOCTYPE declaration is <code>&lt;!DOCTYPE html></code> and is
   case-insensitive in the HTML syntax. DOCTYPEs from earlier versions of
   HTML were longer because the HTML language was SGML-based and therefore
   required a reference to a DTD. With HTML5 this is no longer the case and
   the DOCTYPE is only needed to enable standards mode for documents written
   using the HTML syntax. Browsers already do this for <code>&lt;!DOCTYPE
   html></code>.

  <h3 id=mathml-svg><span class=secno>2.3. </span>MathML and SVG</h3>

  <p>The HTML syntax of HTML5 allows for MathML and SVG elements to be used
   inside a document. E.g. a very simple document using some of the minimal
   syntax features could look like:

  <pre><code>&lt;!doctype html>
&lt;title>SVG in text/html&lt;/title>
&lt;p>
 A green circle:
 <strong>&lt;svg> &lt;circle r="50" cx="50" cy="50" fill="green"/> &lt;/svg></strong>
&lt;/p></code></pre>

  <p>More complex combinations are also possible. E.g. with the SVG
   <code>foreignObject</code> element you could nest MathML, HTML, or both
   inside an SVG fragment that is itself inside HTML.

  <h3 id=syntax-misc><span class=secno>2.4. </span>Miscellaneous</h3>

  <p>There are a few other syntax changes worthy of mentioning:

  <ul>
   <li>HTML now has native support for IRIs, though they can only be fully
    used if the document encoding is UTF-8 or UTF-16.

   <li>The <code>lang</code> attribute takes the empty string in addition to
    a valid language identifier, just like <code>xml:lang</code> does in XML.
  </ul>

  <h2 id=language><span class=secno>3. </span>Language</h2>

  <p>This section is split up in several subsections to more clearly
   illustrate the various differences there are between HTML4 and HTML5.

  <h3 id=new-elements><span class=secno>3.1. </span>New Elements</h3>

  <p>The following elements have been introduced for better structure:

  <ul>
   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-section-element"><code>section</code></a>
     represents a generic document or application section. It can be <a
     href="http://www.w3.org/TR/html5/sections.html#headings-and-sections"
     title="Headings and sections">used together</a> with the
     <code>h1</code>, <code>h2</code>, <code>h3</code>, <code>h4</code>,
     <code>h5</code>, and <code>h6</code> elements to indicate the document
     structure.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-article-element"><code>article</code></a>
     represents an independent piece of content of a document, such as a blog
     entry or newspaper article.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-aside-element"><code>aside</code></a>
     represents a piece of content that is only slightly related to the rest
     of the page.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-hgroup-element"><code>hgroup</code></a>
     represents the header of a section.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-header-element"><code>header</code></a>
     represents a group of introductory or navigational aids.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-footer-element"><code>footer</code></a>
     represents a footer for a section and can contain information about the
     author, copyright information, etc.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/sections.html#the-nav-element"><code>nav</code></a>
     represents a section of the document intended for navigation.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/grouping-content.html#the-figure-element"><code>figure</code></a>
     represents a piece of self-contained flow content, typically referenced
     as a single unit from the main flow of the document.</p>

    <pre><code>&lt;figure>
 &lt;video src="example.webm" controls>&lt;/video>
 &lt;figcaption>Example&lt;/figcaption>
&lt;/figure></code></pre>

    <p><a
     href="http://www.w3.org/TR/html5/grouping-content.html#the-figcaption-element"><code>figcaption</code></a>
     can be used as caption (it is optional).</p>
  </ul>

  <p>Then there are several other new elements:

  <ul>
   <li>
    <p><a
     href="http://www.w3.org/TR/2011/WD-html5-20110525/the-iframe-element.html#the-video-element"><code>video</code></a>
     and <a
     href="http://www.w3.org/TR/2011/WD-html5-20110525/the-iframe-element.html#the-audio-element"><code>audio</code></a>
     for multimedia content. Both provide an API so application authors can
     script their own user interface, but there is also a way to trigger a
     user interface provided by the user agent. <a
     href="http://www.w3.org/TR/2011/WD-html5-20110525/the-iframe-element.html#the-source-element"><code>source</code></a>
     elements are used together with these elements if there are multiple
     streams available of different types.

   <li>
    <p><a
     href="http://www.w3.org/TR/2011/WD-html5-20110525/the-iframe-element.html#the-track-element"><code>track</code></a>
     provides text tracks for the <code>video</code> element.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/the-iframe-element.html#the-embed-element"><code>embed</code></a>
     is used for plugin content.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/text-level-semantics.html#the-mark-element"><code>mark</code></a>
     represents a run of text in one document marked or highlighted for
     reference purposes, due to its relevance in another context.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/the-button-element.html#the-progress-element"><code>progress</code></a>
     represents a completion of a task, such as downloading or when
     performing a series of expensive operations.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/the-button-element.html#the-meter-element"><code>meter</code></a>
     represents a measurement, such as disk usage.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/text-level-semantics.html#the-time-element"><code>time</code></a>
     represents a date and/or time.

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/text-level-semantics.html#the-ruby-element"><code>ruby</code></a>,
     <a
     href="http://dev.w3.org/html5/spec/text-level-semantics.html#the-rt-element"><code>rt</code></a>
     and <a
     href="http://dev.w3.org/html5/spec/text-level-semantics.html#the-rp-element"><code>rp</code></a>
     allow for marking up ruby annotations.

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/text-level-semantics.html#the-bdi-element"><code>bdi</code></a>
     represents a span of text that is to be isolated from its surroundings
     for the purposes of bidirectional text formatting.

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/text-level-semantics.html#the-wbr-element"><code>wbr</code></a>
     represents a line break opportunity.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/the-canvas-element.html#the-canvas-element"><code>canvas</code></a>
     is used for rendering dynamic bitmap graphics on the fly, such as graphs
     or games.

   <li>
    <p><a
     href="http://www.w3.org/TR/2011/WD-html5-20110525/interactive-elements.html#the-command-element"><code>command</code></a>
     represents a command the user can invoke.

   <li>
    <p><a
     href="http://www.w3.org/TR/html5/interactive-elements.html#the-details-element"><code>details</code></a>
     represents additional information or controls which the user can obtain
     on demand. The <a
     href="http://www.w3.org/TR/html5/interactive-elements.html#the-summary-element"><code>summary</code></a>
     element provides its summary, legend, or caption.

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/the-button-element.html#the-datalist-element"><code>datalist</code></a>
     together with the a new <code>list</code> attribute for
     <code>input</code> can be used to make comboboxes:</p>

    <pre><code>&lt;input <strong>list="browsers"</strong>>
&lt;datalist <strong>id="browsers"</strong>>
 &lt;option value="Safari">
 &lt;option value="Internet Explorer">
 &lt;option value="Opera">
 &lt;option value="Firefox">
&lt;/datalist></code></pre>

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/the-button-element.html#the-keygen-element"><code>keygen</code></a>
     represents control for key pair generation.

   <li>
    <p><a
     href="http://dev.w3.org/html5/spec/the-button-element.html#the-output-element"><code>output</code></a>
     represents some type of output, such as from a calculation done through
     scripting.
  </ul>

  <p>The <code>input</code> element's <code>type</code> attribute now has the
   following new values:

  <ul>
   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#telephone-state"><code>tel</code>
    </a>

   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#text-state-and-search-state"><code>search</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#url-state"><code>url</code>
    </a>

   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#e-mail-state"><code>email</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#date-and-time-state"><code>datetime</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#date-state"><code>date</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#month-state"><code>month</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#week-state"><code>week</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#time-state"><code>time</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/states-of-the-type-attribute.html#local-date-and-time-state"><code>datetime-local</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/number-state.html#number-state"><code>number</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/number-state.html#range-state"><code>range</code></a>


   <li><a
    href="http://www.w3.org/TR/html5/number-state.html#color-state"><code>color</code></a>

  </ul>

  <p>The idea of these new types is that the user agent can provide the user
   interface, such as a calendar date picker or integration with the user's
   address book, and submit a defined format to the server. It gives the user
   a better experience as his input is checked before sending it to the
   server meaning there is less time to wait for feedback.

  <h3 id=new-attributes><span class=secno>3.2. </span>New Attributes</h3>

  <p>HTML5 has introduced several new attributes to various elements that
   were already part of HTML4:

  <ul>
   <li>
    <p>The <code>a</code> and <code>area</code> elements now have a
     <code>media</code> attribute for consistency with the <code>link</code>
     element.

   <li>
    <p>The <code>area</code> element, for consistency with the <code>a</code>
     and <code>link</code> elements, now also has the <code>hreflang</code>,
     <code>type</code> and <code>rel</code> attributes.

   <li>
    <p>The <code>base</code> element can now have a <code>target</code>
     attribute as well, mainly for consistency with the <code>a</code>
     element. (This is already widely supported.)

   <li>
    <p>The <code>meta</code> element has a <code>charset</code> attribute now
     as this was already widely supported and provides a nice way to specify
     the <a href="#character-encoding">character encoding</a> for the
     document.

   <li>
    <p>A new <code>autofocus</code> attribute can be specified on the
     <code>input</code> (except when the <code>type</code> attribute is
     <code>hidden</code>), <code>select</code>, <code>textarea</code> and
     <code>button</code> elements. It provides a declarative way to focus a
     form control during page load. Using this feature should enhance the
     user experience as the user can turn it off if the user does not like
     it, for instance.

   <li>
    <p>A new <code>placeholder</code> attribute can be specified on the
     <code>input</code> and <code>textarea</code> elements. It represents a
     hint intended to aid the user with data entry.</p>

    <pre><code>&lt;input type=email <strong>placeholder="a@b.com"</strong>></code></pre>

   <li>
    <p>The new <code>form</code> attribute for <code>input</code>,
     <code>output</code>, <code>select</code>, <code>textarea</code>,
     <code>button</code>, <code>label</code>, <code>object</code> and
     <code>fieldset</code> elements allows for controls to be associated with
     a form. These elements can now be placed anywhere on a page, not just as
     descendants of the <code>form</code> element, and still be associated
     with a <code>form</code>.</p>

    <pre><code>&lt;label>Email:
 &lt;input type=email <strong>form=foo</strong> name=email>
&lt;/label>
&lt;form <strong>id=foo</strong>>&lt;/form></code></pre>

   <li>
    <p>The new <code>required</code> attribute applies to <code>input</code>
     (except when the <code>type</code> attribute is <code>hidden</code>,
     <code>image</code> or some button type such as <code>submit</code>),
     <code>select</code> and <code>textarea</code>. It indicates that the
     user has to fill in a value in order to submit the form. For
     <code>select</code>, the first <code>option</code> element has to be a
     placeholder with an empty value.

    <pre><code>&lt;label>Color: &lt;select name=color <strong>required</strong>>
 &lt;option <strong>value=""</strong>>Choose one
 &lt;option>Red
 &lt;option>Green
 &lt;option>Blue
&lt;/select>&lt;/label></code></pre>

   <li>
    <p>The <code>fieldset</code> element now allows the <code>disabled</code>
     attribute which disables all descendant controls when specified, and the
     <code>name</code> attribute which can be used for script access.

   <li>
    <p>The <code>input</code> element has several new attributes to specify
     constraints: <code>autocomplete</code>, <code>min</code>,
     <code>max</code>, <code>multiple</code>, <code>pattern</code> and
     <code>step</code>. As mentioned before it also has a new
     <code>list</code> attribute which can be used together with the
     <code>datalist</code> element. It also now has the <code>width</code>
     and <code>height</code> attributes to specify the dimensions of the
     image when using <code>type=image</code>.

   <li>
    <p>The <code>input</code> and <code>textarea</code> elements have a new
     attribute named <code>dirname</code> that causes the directionality of
     the control as set by the user to be submitted as well.

   <li>
    <p>The <code>textarea</code> element also has two new attributes,
     <code>maxlength</code> and <code>wrap</code> which control max input
     length and submitted line wrapping behavior, respectively.

   <li>
    <p>The <code>form</code> element has a <code>novalidate</code> attribute
     that can be used to disable form validation submission (i.e. the form
     can always be submitted).

   <li>
    <p>The <code>input</code> and <code>button</code> elements have
     <code>formaction</code>, <code>formenctype</code>,
     <code>formmethod</code>, <code>formnovalidate</code>, and
     <code>formtarget</code> as new attributes. If present, they override the
     <code>action</code>, <code>enctype</code>, <code>method</code>,
     <code>novalidate</code>, and <code>target</code> attributes on the
     <code>form</code> element.</p>

   <li>
    <p>The <code>menu</code> element has two new attributes:
     <code>type</code> and <code>label</code>. They allow the element to
     transform into a menu as found in typical user interfaces as well as
     providing for context menus in conjunction with the global
     <code>contextmenu</code> attribute.

   <li>
    <p>The <code>style</code> element has a new <code>scoped</code> attribute
     which can be used to enable scoped style sheets. Style rules within such
     a <code>style</code> element only apply to the local tree.

   <li>
    <p>The <code>script</code> element has a new attribute called
     <code>async</code> that influences script loading and execution.

   <li>
    <p>The <code>html</code> element has a new attribute called
     <code>manifest</code> that points to an application cache manifest used
     in conjunction with the API for offline Web applications.

   <li>
    <p>The <code>link</code> element has a new attribute called
     <code>sizes</code>. It can be used in conjunction with the
     <code>icon</code> relationship (set through the <code>rel</code>
     attribute; can be used for e.g. favicons) to indicate the size of the
     referenced icon. Thus allowing for icons of distinct dimensions.

   <li>
    <p>The <code>ol</code> element has a new attribute called
     <code>reversed</code>. When present, it indicates that the list order is
     descending.

   <li>
    <p>The <code>iframe</code> element has three new attributes called
     <code>sandbox</code>, <code>seamless</code>, and <code>srcdoc</code>
     which allow for sandboxing content, e.g. blog comments.
  </ul>

  <p>Several attributes from HTML4 now apply to all elements. These are
   called global attributes: <code>accesskey</code>, <code>class</code>,
   <code>dir</code>, <code>id</code>, <code>lang</code>, <code>style</code>,
   <code>tabindex</code> and <code>title</code>. Additionally, XHTML 1.0 only
   allowed <code>xml:space</code> on some elements, which is now allowed on
   all elements in XHTML documents.

  <p>There are also several new global attributes:

  <ul>
   <li>The <code>contenteditable</code> attribute indicates that the element
    is an editable area. The user can change the contents of the element and
    manipulate the markup.

   <li>The <code>contextmenu</code> attribute can be used to point to a
    context menu provided by the author.

   <li>The <code>data-<var>*</var></code> collection of author-defined
    attributes. Authors can define any attribute they want as long as they
    prefix it with <code>data-</code> to avoid clashes with future versions
    of HTML. The only requirement on these attributes is that they are not
    used for user agent extensions.

   <li>The <code>draggable</code> and <code>dropzone</code> attributes can be
    used together with the new drag &amp; drop API.

   <li>The <code>hidden</code> attribute indicates that an element is not
    yet, or is no longer, relevant.

   <li>The <code>role</code> and <code>aria-<var>*</var></code> collection
    attributes which can be used to instruct assistive technology.

   <li>The <code>spellcheck</code> attribute allows for hinting whether
    content can be checked for spelling or not.
  </ul>

  <p>HTML5 also makes all event handler attributes from HTML4, which take the
   form <code>on<var>event-name</var></code>, global attributes and adds
   several new event handler attributes for new events it defines. E.g. the
   <code>play</code> event which is used by the API for the media elements
   (<code>video</code> and <code>audio</code>).

  <h3 id=changed-elements><span class=secno>3.3. </span>Changed Elements</h3>

  <p>These elements have slightly modified meanings in HTML5 to better
   reflect how they are used on the Web or to make them more useful:

  <ul>
   <li>
    <p>The <code>a</code> element without an <code>href</code> attribute now
     represents a placeholder for where a link otherwise might have been
     placed. It can also contain flow content rather than being restricted to
     phrasing content.

   <li>
    <p>The <code>address</code> element is now scoped by the new concept of
     sectioning.

   <li>
    <p>The <code>b</code> element now represents a span of text to which
     attention is being drawn for utilitarian purposes without conveying any
     extra importance and with no implication of an alternate voice or mood,
     such as key words in a document abstract, product names in a review,
     actionable words in interactive text-driven software, or an article
     lede.

   <li>
    <p>The <code>cite</code> element now solely represents the title of a
     work (e.g. a book, a paper, an essay, a poem, a score, a song, a script,
     a film, a TV show, a game, a sculpture, a painting, a theatre
     production, a play, an opera, a musical, an exhibition, a legal case
     report, etc). Specifically the example in HTML4 where it is used to mark
     up the name of a person is no longer considered conforming.

   <li>
    <p>The <code>dl</code> element now represents an association list of
     name-value groups, and is no longer said to be appropriate for dialogue.

   <li>
    <p>The <code>head</code> element no longer allows the <code>object</code>
     element as child.

   <li>
    <p>The <code>hr</code> element now represents a paragraph-level thematic
     break.

   <li>
    <p>The <code>i</code> element now represents a span of text in an
     alternate voice or mood, or otherwise offset from the normal prose in a
     manner indicating a different quality of text, such as a taxonomic
     designation, a technical term, an idiomatic phrase from another
     language, a thought, or a ship name in Western texts.

   <li>
    <p>For the <code>label</code> element the browser should no longer move
     focus from the label to the control unless such behavior is standard for
     the underlying platform user interface.

   <li>
    <p>The <code>menu</code> element is redefined to be useful for toolbars
     and context menus.

   <li>
    <p>The <code>s</code> element now represents contents that are no longer
     accurate or no longer relevant.

   <li>
    <p>The <code>small</code> element now represents side comments such as
     small print.

   <li>
    <p>The <code>strong</code> element now represents importance rather than
     strong emphasis.

   <li>
    <p>The <code>u</code> element now represents a span of text with an
     unarticulated, though explicitly rendered, non-textual annotation, such
     as labeling the text as being a proper name in Chinese text (a Chinese
     proper name mark), or labeling the text as being misspelt.
  </ul>

  <h3 id=changed-attributes><span class=secno>3.4. </span>Changed Attributes</h3>

  <p>The <code>value</code> attribute for the <code>li</code> element is no
   longer deprecated as it is not presentational. The same goes for the
   <code>start</code> attribute of the <code>ol</code> element.

  <p>The <code>target</code> attribute for the <code>a</code> and
   <code>area</code> elements is no longer deprecated, as it is useful in Web
   applications, e.g. in conjunction with <code>iframe</code>.

  <p>The <code>type</code> attribute on <code>script</code> and
   <code>style</code> is no longer required if the scripting language is
   ECMAScript and the styling language is CSS respectively.

  <p>The <code>border</code> attribute on <code>table</code> only allows the
   values "1" and the empty string.

  <p>The following attributes are allowed but authors are discouraged from
   using them and instead strongly encouraged to use an alternative solution:

  <ul>
   <li>
    <p>The <code>border</code> attribute on <code>img</code>. It is required
     to have the value "<code>0</code>" when present. Authors can use CSS
     instead.

   <li>
    <p>The <code>language</code> attribute on <code>script</code>. It is
     required to have the value "<code>JavaScript</code>" (case-insensitive)
     when present and cannot conflict with the <code>type</code> attribute.
     Authors can simply omit it as it has no useful function.

   <li>
    <p>The <code>name</code> attribute on <code>a</code>. Authors can use the
     <code>id</code> attribute instead.

   <li>
    <p>The <code>summary</code> attribute on <code>table</code>. The HTML5
     draft defines several alternative solutions.

   <li>
    <p>The <code>width</code> and <code>height</code> attributes on
     <code>img</code> and other elements are no longer allowed to contain
     percentages.
  </ul>

  <h3 id=absent-elements><span class=secno>3.5. </span>Absent Elements</h3>

  <p>The elements in this section are not to be used by authors. User agents
   will still have to support them and various sections in HTML5 define how.
   E.g. the obsolete <code>isindex</code> element is handled by the parser
   section.

  <p>The following elements are not in HTML5 because their effect is purely
   presentational and their function is better handled by CSS:

  <ul>
   <li><code>basefont</code>

   <li><code>big</code>

   <li><code>center</code>

   <li><code>font</code>

   <li><code>strike</code>

   <li><code>tt</code>
  </ul>

  <p>The following elements are not in HTML5 because using them damages
   usability and accessibility:

  <ul>
   <li><code>frame</code>

   <li><code>frameset</code>

   <li><code>noframes</code>
  </ul>

  <p>The following elements are not included because they have not been used
   often, created confusion, or their function can be handled by other
   elements:

  <ul>
   <li><code>acronym</code> is not included because it has created a lot of
    confusion. Authors are to use <code>abbr</code> for abbreviations.

   <li><code>applet</code> has been obsoleted in favor of
    <code>object</code>.

   <li><code>isindex</code> usage can be replaced by usage of form controls.

   <li><code>dir</code> has been obsoleted in favor of <code>ul</code>.
  </ul>

  <p>Finally the <code>noscript</code> element is only conforming in the HTML
   syntax. It is not included in the XML syntax as its usage relies on an
   HTML parser.

  <h3 id=absent-attributes><span class=secno>3.6. </span>Absent Attributes</h3>

  <p>Some attributes from HTML4 are no longer allowed in HTML5. The
   specification defines how user agents should process them in legacy
   documents, but authors must not use them and they will not validate.

  <p>HTML5 <a
   href="http://www.w3.org/TR/html5/obsolete.html#non-conforming-features"
   title="Non-conforming features">has advice</a> on what you can use
   instead.

  <ul>
   <li><code>rev</code> and <code>charset</code> attributes on
    <code>link</code> and <code>a</code>.

   <li><code>shape</code> and <code>coords</code> attributes on
    <code>a</code>.

   <li><code>longdesc</code> attribute on <code>img</code> and
    <code>iframe</code>.

   <li><code>target</code> attribute on <code>link</code>.

   <li><code>nohref</code> attribute on <code>area</code>.

   <li><code>profile</code> attribute on <code>head</code>.

   <li><code>version</code> attribute on <code>html</code>.

   <li><code>name</code> attribute on <code>img</code> (use <code>id</code>
    instead).

   <li><code>scheme</code> attribute on <code>meta</code>.

   <li><code>archive</code>, <code>classid</code>, <code>codebase</code>,
    <code>codetype</code>, <code>declare</code> and <code>standby</code>
    attributes on <code>object</code>.

   <li><code>valuetype</code> and <code>type</code> attributes on
    <code>param</code>.

   <li><code>axis</code> and <code>abbr</code> attributes on <code>td</code>
    and <code>th</code>.

   <li><code>scope</code> attribute on <code>td</code>.

   <li><code>summary</code> attribute on <code>table</code>.
  </ul>

  <p>In addition, HTML5 has none of the presentational attributes that were
   in HTML4 as their functions are better handled by CSS:

  <ul>
   <li><code>align</code> attribute on <code>caption</code>,
    <code>iframe</code>, <code>img</code>, <code>input</code>,
    <code>object</code>, <code>legend</code>, <code>table</code>,
    <code>hr</code>, <code>div</code>, <code>h1</code>, <code>h2</code>,
    <code>h3</code>, <code>h4</code>, <code>h5</code>, <code>h6</code>,
    <code>p</code>, <code>col</code>, <code>colgroup</code>,
    <code>tbody</code>, <code>td</code>, <code>tfoot</code>, <code>th</code>,
    <code>thead</code> and <code>tr</code>.

   <li><code>alink</code>, <code>link</code>, <code>text</code> and
    <code>vlink</code> attributes on <code>body</code>.

   <li><code>background</code> attribute on <code>body</code>.

   <li><code>bgcolor</code> attribute on <code>table</code>, <code>tr</code>,
    <code>td</code>, <code>th</code> and <code>body</code>.

   <li><code>border</code> attribute on <code>object</code>.

   <li><code>cellpadding</code> and <code>cellspacing</code> attributes on
    <code>table</code>.

   <li><code>char</code> and <code>charoff</code> attributes on
    <code>col</code>, <code>colgroup</code>, <code>tbody</code>,
    <code>td</code>, <code>tfoot</code>, <code>th</code>, <code>thead</code>
    and <code>tr</code>.

   <li><code>clear</code> attribute on <code>br</code>.

   <li><code>compact</code> attribute on <code>dl</code>, <code>menu</code>,
    <code>ol</code> and <code>ul</code>.

   <li><code>frame</code> attribute on <code>table</code>.

   <li><code>frameborder</code> attribute on <code>iframe</code>.

   <li><code>height</code> attribute on <code>td</code> and <code>th</code>.

   <li><code>hspace</code> and <code>vspace</code> attributes on
    <code>img</code> and <code>object</code>.

   <li><code>marginheight</code> and <code>marginwidth</code> attributes on
    <code>iframe</code>.

   <li><code>noshade</code> attribute on <code>hr</code>.

   <li><code>nowrap</code> attribute on <code>td</code> and <code>th</code>.

   <li><code>rules</code> attribute on <code>table</code>.

   <li><code>scrolling</code> attribute on <code>iframe</code>.

   <li><code>size</code> attribute on <code>hr</code>.

   <li><code>type</code> attribute on <code>li</code>, <code>ol</code> and
    <code>ul</code>.

   <li><code>valign</code> attribute on <code>col</code>,
    <code>colgroup</code>, <code>tbody</code>, <code>td</code>,
    <code>tfoot</code>, <code>th</code>, <code>thead</code> and
    <code>tr</code>.

   <li><code>width</code> attribute on <code>hr</code>, <code>table</code>,
    <code>td</code>, <code>th</code>, <code>col</code>, <code>colgroup</code>
    and <code>pre</code>.
  </ul>

  <h2 id=apis><span class=secno>4. </span>APIs</h2>

  <p>HTML5 introduces a number of APIs that help in creating Web
   applications. These can be used together with the new elements introduced
   for applications:

  <ul>
   <li>An API for playing of video and audio which can be used with the new
    <code>video</code> and <code>audio</code> elements.

   <li>An API that enables offline Web applications.

   <li>An API that allows a Web application to register itself for certain
    protocols or media types.

   <li>Editing API in combination with a new global
    <code>contenteditable</code> attribute.

   <li>Drag &amp; drop API in combination with a <code>draggable</code>
    attribute.

   <li>API that exposes the history and allows pages to add to it to prevent
    breaking the back button.
  </ul>

  <h3 id=htmldocument-extensions><span class=secno>4.1. </span>Extensions to
   <code>HTMLDocument</code></h3>

  <p>HTML5 has extended the <code>HTMLDocument</code> interface from DOM
   Level 2 HTML in a number of ways. The interface is now implemented on
   <em>all</em> objects implementing the <code>Document</code> interface so
   it stays meaningful in a compound document context. It also has several
   noteworthy new members:

  <ul>
   <li>
    <p><code>getElementsByClassName()</code> to select elements by their
     class name. The way this method is defined will allow it to work for any
     content with <code>class</code> attributes and a <code>Document</code>
     object such as SVG and MathML.

   <li>
    <p><code>innerHTML</code> as an easy way to parse and serialize an HTML
     or XML document. This attribute was previously only available on
     <code>HTMLElement</code> in Web browsers and not part of any standard.

   <li>
    <p><code>activeElement</code> and <code>hasFocus</code> to determine
     which element is currently focused and whether the <code>Document</code>
     has focus respectively.
  </ul>

  <h3 id=htmlelement-extensions><span class=secno>4.2. </span>Extensions to
   <code>HTMLElement</code></h3>

  <p>The <code>HTMLElement</code> interface has also gained several
   extensions in HTML5:

  <ul>
   <li>
    <p><code>getElementsByClassName()</code> which is basically a scoped
     version of the one found on <code>HTMLDocument</code>.

   <li>
    <p><code>innerHTML</code> as found in Web browsers today. It is also
     defined to work in XML context (when it is used in an XML document).

   <li>
    <p><code>classList</code> is a convenient accessor for
     <code>className</code>. The object it returns, exposes methods
     (<code>contains()</code>, <code>add()</code>, <code>remove()</code>, and
     <code>toggle()</code>) for manipulating the element's classes. The
     <code>a</code>, <code>area</code> and <code>link</code> elements have a
     similar attribute called <code>relList</code> that provides the same
     functionality for the <code>rel</code> attribute.
  </ul>

  <h2 id=changelog><span class=secno>5. </span>HTML5 Changelogs</h2>

  <p>The changelogs in this section indicate what has been changed between
   publications of the HTML5 drafts. Rationale for changes can be found in
   the <a
   href="http://lists.w3.org/Archives/Public/public-html/"><code>public-html@w3.org</code></a>
   and <a
   href="http://lists.whatwg.org/pipermail/whatwg-whatwg.org/"><code>whatwg@whatwg.org</code></a>
   mailing list archives, and the <a
   href="http://blog.whatwg.org/category/weekly-review">WHATWG Weekly</a>
   series of blog posts. More fundamental rationale is being collected on the
   WHATWG <a href="http://wiki.whatwg.org/wiki/Rationale">Rationale</a> wiki
   page. Many editorial and minor technical changes are not included in these
   changelogs. Implementors are strongly encouraged to follow the development
   of the main specification on a frequent basis so they become aware of all
   changes that affect them early on.

  <p>The changes in the changelogs are in rough chronological order.</p>
  <!-- rev 6139 - 6142 -->
  <!--<li>The <code>cross-origin</code> attribute has been added to <code>img</code>, <code>video</code> and <code>audio</code> to use CORS. [<cite><span>CORS</span></cite>]
     <li>The <code>external</code> attribute has been added on <code>window</code> and has the members <code>AddSearchProvider()</code> and <code>IsSearchProviderInstalled()</code>.-->

  <h3 id=changes-2011-04-05><span class=secno>5.1. </span>Changes since 5
   April 2011</h3>
  <!-- rev 5974 - 6139 -->

  <ul>
   <li>Support for the <code>javascript:</code> scheme in <code>img</code>,
    <code>object</code>, CSS, etc, has been dropped.

   <li>The <code>toBlob()</code> method has been added to
    <code>canvas</code>.

   <li>The <code>drawFocusRing()</code> method on the <code>canvas</code> 2d
    context has been split into two methods,
    <code>drawSystemFocusRing()</code> and
    <code>drawCustomFocusRing()</code>.

   <li>The <code>values</code> attribute on <code>PropertyNodeList</code> has
    been replaced with a <code>getValues()</code> method.

   <li>The <code>select</code> event has been specified.

   <li>The <code>selectDirection</code> IDL attribute has been added to
    <code>input</code> and <code>textarea</code>.

   <li>The <code>:enabled</code> and <code>:disabled</code> pseudo-classes
    now match <code>fieldset</code>, and the <code>:indeterminate</code>
    pseudo-class can now match <code>progress</code>.

   <li>The <code>getKind()</code> method has been added to
    <code>TrackList</code>.

   <li>The <code>MediaController</code> API and the <code>mediagroup</code>
    attribute have been added to synchronize playback of media elements.

   <li>Some ARIA defaults have changed, and it is now invalid to specify ARIA
    attributes that match the defaults.

   <li>The <code>getName()</code> method on <code>TrackList</code> was
    renamed to <code>getLabel()</code>.

   <li>The <code>border</code> attribute on <code>table</code> is now
    conforming.

   <li>The <code>u</code> element is now conforming.

   <li>The <code>summary</code> attribute on <code>table</code> is now
    non-conforming.

   <li>The <code>audio</code> attribute on <code>video</code> was changed to
    a boolean <code>muted</code> attribute.

   <li>The <code>Content-Language</code> meta pragma is now non-conforming.
  </ul>

  <h3 id=changes-2011-01-13><span class=secno>5.2. </span>Changes from 13
   January 2011 to 5 April 2011</h3>
  <!-- rev 5779 - 5974 -->

  <ul>
   <li>The <code>pushState</code> and <code>replaceState</code> features have
    been changed based on implementation feedback in Firefox, and
    <code>history.state</code> has been introduced.

   <li>The <code>tracks</code> IDL attribute on media elements has been
    renamed to <code>textTracks</code>.

   <li>Event handler content attributes now support ECMAScript strict mode.

   <li>The <code>forminput</code> and <code>formchange</code> events, and the
    <code>dispatchFormInput()</code> and <code>dispatchFormChange()</code>
    methods have been dropped.

   <li>The <code>rel</code> keywords <code>archives</code>, <code>up</code>,
    <code>last</code>, <code>index</code>, <code>first</code> and related
    synonyms have been dropped.

   <li>Removing a media element from the DOM and inserting it again in the
    same script now doesn't pause the media element.

   <li>The <code>video</code> element's letterboxing rules are now specified
    in terms of CSS 'object-fit'.

   <li>Cross-origin fonts now don't leak information about the font when
    drawn on a <code>canvas</code>.

   <li>The character encoding declaration is now allowed to be within the
    first 1024 bytes instead of the first 512 bytes.

   <li>The <code>onerror</code> event handler on <code>window</code> is now
    invoked for compile-time script errors as well as runtime errors.

   <li>Script-inserted <code>script</code> elements now have
    <code>async</code> default to <code>true</code>, which can be set to
    <code>false</code> to make the scripts execute in insertion order.

   <li>The <code>atob()</code> and <code>btoa()</code> methods have been
    specified.

   <li>The suggested file extension for application cache manifest files has
    been changed from <code>.manifest</code> to <code>.appcache</code>.

   <li>The <code>action</code> and <code>formaction</code> attributes are no
    longer allowed to have the empty string as value.
  </ul>

  <h3 id=changes-2010-10-19><span class=secno>5.3. </span>Changes from 19
   October 2010 to 13 January 2011</h3>
  <!-- rev 5643 - 5779 -->

  <ul>
   <li>Drag and drop model was refined.

   <li>A new global <code>dropzone</code> attribute was added.

   <li>A new <code>bdi</code> element was added to aid with user-generated
    content that may have bidi implications.

   <li>The <code>dir</code> attribute gained a new "<code>auto</code>" value.

   <li>A <code>dirname</code> attribute was added to <code>input</code>
    elements. When specified the directionality as specified by the user will
    be submitted to the server as well.

   <li>A new <code>track</code> element and associated TextTrack API were
    added for video text tracks.
  </ul>

  <p>The <code>getSelection()</code> API moved to a separate <a
   href="http://html5.org/specs/dom-range.html">DOM Range</a> draft.
   Similarly <code>UndoManager</code> has been removed from the W3C copy of
   HTML5 for now as it is not ready yet.

  <h3 id=changes-2010-06-24><span class=secno>5.4. </span>Changes from 24
   June 2010 to 19 October 2010</h3>
  <!-- rev 5108 - 5642 -->

  <ul>
   <li>Numerous changes to the HTML parsing algorithm based on implementation
    feedback.

   <li>The <code>hidden</code> attribute now works for table-related
    elements.

   <li>The <code>canvas</code> <code>getContext()</code> method is now
    defined to be able to handle multiple contexts better.

   <li>The media elements' <code>startTime</code> IDL attribute was renamed
    to <code>initialTime</code> and <code>startOffsetTime</code> was added.

   <li>The <code>prefetch</code> link relationship can now be used on
    <code>a</code> elements.

   <li>The <code>datetime</code> attribute of <code>ins</code> and
    <code>del</code> no longer requires a time to be specified.

   <li>Using PUT and DELETE as HTTP methods for the <code>form</code> element
    is no longer supported.

   <li>The <code>s</code> element is no longer deprecated.

   <li>The <code>video</code> element has a new <code>audio</code> attribute.
  </ul>

  <p>Per usual, lots of other minor fixes have been made as well.

  <h3 id=changes-2010-03-04><span class=secno>5.5. </span>Changes from 4
   March 2010 to 24 June 2010</h3>
  <!-- rev 4647 - 5107 -->

  <ul>
   <li>The <code>ping</code> attribute has been removed from the W3C version
    of HTML5.

   <li>The <code>title</code> element is optional for <code>iframe</code>
    <code>srcdoc</code> documents and other scenarios where a title is
    already available. As is the case with email.

   <li><code>keywords</code> is now a standard metadata name for the
    <code>meta</code> element.

   <li>The <code>allow-top-navigation</code> value has been added for the
    <code>sandbox</code> attribute on the <code>iframe</code> element. It
    allows the embedded content to navigate its parent when specified.

   <li>The <code>wbr</code> element has been added.

   <li>The <code>alternate</code> keyword for the <code>rel</code> attribute
    of the <code>link</code> element can now be used to point to feeds again,
    even if the feed is not an alternative for the document.

   <li>The HTML to Atom mapping has been removed from the W3C version of
    HTML5.
  </ul>

  <p>In addition lots of minor changes, clarifications, and fixes have been
   made to the document.

  <h3 id=changes-2009-08-25><span class=secno>5.6. </span>Changes from 25
   August 2009 to 4 March 2010</h3>
  <!-- since rev 3673 -->

  <ul>
   <li>The <code>dialog</code> element has been removed. A section with
    advice on how to mark up conversations has effectively replaced it.

   <li><code>document.head</code> has been introduced to provide convenient
    access to the <code>head</code> element from script.

   <li>The link type <code title="">feed</code> has been removed. <code
    title=rel-alternate>alternate</code> with specific media types is to be
    used instead.

   <li><code>createHTMLDocument()</code> has been introduced as API to allow
    easy creation of HTML documents.

   <li>Both the <code>meter</code> and <code>progress</code> elements no
    longer have "magic" processing of their contents because it could not be
    made to work internationally.

   <li>The <code>meter</code> and <code>progress</code> elements, as well as
    the <code>output</code> element, can now be labeled using the
    <code>label</code> element.

   <li>A new media type, <code>text/html-sandboxed</code>, was introduced to
    allow hosting of potentially hostile content without it causing harm.

   <li>A <code>srcdoc</code> attribute for the <code>iframe</code> element
    was introduced to allow embedding of potentially hostile content inline.
    It is expected to be used together with the <code>sandbox</code> and
    <code>seamless</code> attributes.

   <li>The <code>figure</code> element now uses a new element
    <code>figcaption</code> rather than <code>legend</code> because people
    want to use HTML5 long before it reaches W3C Recommendation.

   <li>The <code>details</code> element now uses a new element
    <code>summary</code> for exactly the same reason.

   <li>The <code>autobuffer</code> attribute on media elements was renamed to
    <code>preload</code>.
  </ul>

  <p>A whole lot of other smaller issues have also been resolved. The above
   list summarizes what is thought to be of primary interest to authors.

  <p>In addition to all of the above, Microdata, the 2D context API for
   <code>canvas</code>, and Web Messaging (<code>postMessage()</code> API)
   have been split into their own drafts at the W3C (the WHATWG still
   publishes a version of HTML5 that includes them):

  <ul>
   <li><a href="http://dev.w3.org/html5/md/">HTML Microdata</a>

   <li><a href="http://dev.w3.org/html5/2dcontext/">HTML Canvas 2D
    Context</a>

   <li><a href="http://dev.w3.org/html5/postmsg/">HTML5 Web Messaging</a>
  </ul>

  <p>Specific microdata vocabularies are gone altogether in the W3C draft of
   HTML5 and are not published as a separate draft. The WHATWG draft of HTML5
   still includes them.

  <h3 id=changes-2009-04-23><span class=secno>5.7. </span>Changes from 23
   April 2009 to 25 August 2009</h3>
  <!-- since rev 2975 -->

  <ul>
   <li>When the <code>time</code> element is empty user agents have to render
    the time in a locale-specific manner.

   <li>The <code>load</code> event is dispatched at <code>Window</code>, but
    now has <code>Document</code> as its target.

   <li><code>pushState()</code> now affects the <code>Referer</code> (sic)
    header.

   <li><code>onundo</code> and <code>onredo</code> are now on
    <code>Window</code>.

   <li>Media elements now have a <code>startTime</code> member that indicates
    where the current resource starts.

   <li><code>header</code> has been renamed to <code>hgroup</code> and a new
    <code>header</code> element has been introduced.

   <li><code>createImageData()</code> now also takes <code>ImageData</code>
    objects.

   <li><code>createPattern()</code> can now take a <code>video</code> element
    as argument too.

   <li>The <code>footer</code> element is no longer allowed in
    <code>header</code> and <code>header</code> is not allowed in
    <code>address</code> or <code>footer</code>.

   <li>A new control has been introduced: <code>&lt;input type="tel"></code>

   <li>The Command API now works for all elements.

   <li><code>accesskey</code> is now properly defined.

   <li><code>section</code> and <code>article</code> now take a
    <code>cite</code> attribute.

   <li>A new feature called Microdata has been introduced which allows people
    to embed custom data structures in their HTML documents.

   <li>Using the Microdata model three predefined vocabularies have also been
    included: vCard, vEvent, and a model for licensing.

   <li>Drag and drop has been updated to work with the Microdata model.

   <li>The <a href="http://hsivonen.iki.fi/last-html-quirk/">last of the
    parsing quirks</a> has been defined.</li>
   <!-- don't kill my easter egg -->

   <li><code>textLength</code> has been added as member of the
    <code>textarea</code> element.

   <li>The <code>rp</code> element now takes phrasing content rather than a
    single character.

   <li><code>location.reload()</code> is now defined.

   <li>The <code>hashchange</code> event now fires asynchronously.

   <li>Rules for compatibility with XPath 1.0 and XSLT 1.0 have been added.

   <li>The <code>spellcheck</code> IDL attribute now maps to a
    <code>DOMString</code>.

   <li><code>hasFeature()</code> support has been reduced to a minimum.

   <li>The <code>Audio()</code> constructor sets the <code>autobuffer</code>
    attribute.

   <li>The <code>td</code> element is no longer allowed in
    <code>thead</code>.

   <li>The <code>input</code> element and <code>DataTransfer</code> object
    now have a <code>files</code> IDL attribute.

   <li>The <code>datagrid</code> and <code>bb</code> have been removed due to
    their design not being agreed upon.

   <li>The cue range API has been removed from the media elements.

   <li>Support for WAI-ARIA has been integrated.
  </ul>

  <p>On top of this list quite a few minor clarifications, typos, issues
   specific to implementors, and other small problems have been resolved.

  <p>In addition, the following parts of HTML5 have been taken out and will
   likely be further developed at the IETF:

  <ul>
   <li>Definition of URLs.

   <li>Definition of Content-Type sniffing.
  </ul>

  <h3 id=changes-2009-02-12><span class=secno>5.8. </span>Changes from 12
   February 2009 to 23 April 2009</h3>

  <ul>
   <li>A new global attribute called <code>spellcheck</code> has been added.

   <li>Defined that ECMAScript <code>this</code> in the global object returns
    a <code>WindowProxy</code> object rather than the <code>Window</code>
    object.

   <li>The <code>value</code> IDL attribute for <code>input</code> elements
    in the File Upload state is now defined.

   <li>Definition of <code>designMode</code> was changed to be more in line
    with legacy implementations.

   <li>The <code>drawImage()</code> method of the 2D drawing API can now take
    a <code>video</code> element as well.

   <li>The way media elements load resources has been changed.

   <li><code>document.domain</code> is now IPv6-compatible.

   <li>The <code>video</code> element gained an <code>autobuffer</code>
    boolean attribute that serves as a hint.

   <li>You are now allowed to specify the <code>meta</code> element with a
    <code>charset</code> attribute in XML documents if the value of that
    attribute matches the encoding of the document. (Note that it does not
    specify the value, it is just a talisman.)

   <li>The <code>bufferingRate</code> and <code>bufferingThrottled</code>
    members of media elements have been removed.

   <li>The media element resource selection algorithm is now asynchronous.

   <li>The <code>postMessage()</code> API now takes an array of
    <code>MessagePort</code> objects rather than just one.

   <li>The second argument of the <code>add()</code> method on the
    <code>select</code> element and the <code>options</code> member of the
    <code>select</code> element is now optional.

   <li>The <code>action</code>, <code>enctype</code>, <code>method</code>,
    <code>novalidate</code>, and <code>target</code> attributes on
    <code>input</code> and <code>button</code> elements have been renamed to
    <code>formaction</code>, <code>formenctype</code>,
    <code>formmethod</code>, <code>formnovalidate</code>, and
    <code>formtarget</code>.

   <li>A "storage mutex" concept has been added to deal with separate pages
    trying to change a storage object (<code>document.cookie</code> and
    <code>localStorage</code>) at the same time. The <code>Navigator</code>
    gained a <code>getStorageUpdates()</code> method to allow it to be
    explicitly released.

   <li>A syntax for SVG similar to MathML is now defined so that SVG can be
    included in <code>text/html</code> resources.

   <li>The <code>placeholder</code> attribute has been added to the
    <code>textarea</code> element.

   <li>Added a <code>keygen</code> element for key pair generation.

   <li>The <code>datagrid</code> element was revised to make the API more
    asynchronous and allow for unloaded parts of the grid.
  </ul>

  <p>In addition, several parts of HTML5 have been taken out and will be
   further developed by the Web Applications Working Group as standalone
   specifications:

  <ul>
   <li><a href="http://dev.w3.org/html5/websockets/">WebSocket API</a>

   <li><a
    href="http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol">WebSocket
    protocol</a>

   <li><a href="http://dev.w3.org/html5/eventsource/">Server-Sent Events</a>

   <li><a href="http://dev.w3.org/html5/webstorage/">Web Storage</a>
    (<code>localStorage</code> and <code>sessionStorage</code>)

   <li><a href="http://dev.w3.org/html5/webdatabase/">Web SQL Database</a>
  </ul>

  <h3 id=changes-2008-06-10><span class=secno>5.9. </span>Changes from 10
   June 2008 to 12 February 2009</h3>

  <ul>
   <li>The <code>data</code> member of <code>ImageData</code> objects has
    been changed from an array to a <code>CanvasPixelArray</code> object.

   <li>Shadows are now required from implementations of the
    <code>canvas</code> element and its API.

   <li>Security model for <code>canvas</code> is clarified.

   <li>Various changes to the processing model of <code>canvas</code> have
    been made in response to implementation and author feedback. E.g.
    clarifying what happens when NaN and Infinity are passed and fixing the
    definitions of <code>arc()</code> and <code>arcTo()</code>.

   <li><code>innerHTML</code> in XML was slightly changed to improve
    round-tripping.

   <li>The <code>toDataURL()</code> method on the <code>canvas</code> element
    now supports setting a quality level when the media type argument is
    <code>image/jpeg</code>.

   <li>The <code>poster</code> attribute of the <code>video</code> element
    now affects its intrinsic dimensions.

   <li>The behavior of the <code>type</code> attribute of the
    <code>link</code> element has been clarified.

   <li>Sniffing is now allowed for <code>link</code> when the expected type
    is an image.

   <li>A section on URLs is introduced dealing with how URL values are to be
    interpreted and what exactly authors are required to do. Every feature of
    the specification that uses URLs has been reworded to take the new URL
    section into account.

   <li>It is now explicit that the <code>href</code> attribute of the
    <code>base</code> element does not depend on <code>xml:base</code>.

   <li>It is now defined what the behavior should be when the base URL
    changes.

   <li>URL decomposition IDL attributes are now more aligned with Internet
    Explorer.

   <li>The <code>xmlns</code> attribute with the value
    <code>http://www.w3.org/1999/xhtml</code> is now allowed on all HTML
    elements.

   <li><code>data-<var>*</var></code> attributes and custom attributes on the
    <code>embed</code> element now have to match the XML <code>Name</code>
    production and cannot contain a colon.

   <li>WebSocket API is introduced for bidirectional communication with a
    server.

   <li>The default value of <code>volume</code> on media elements is now 1.0
    rather than 0.5.

   <li><code>event-source</code> was renamed to <code>eventsource</code>
    because no other HTML element uses a hyphen.

   <li>A message channel API has been introduced augmenting
    <code>postMessage()</code>.

   <li>A new element named <code>bb</code> has been added. It represents a
    user agent command that the user can invoke.

   <li>The <code>addCueRange()</code> method on media elements has been
    modified to take an identifier which is exposed in the callbacks.

   <li>It is now defined how to mutate a DOM into an infoset.

   <li>The <code>parent</code> attribute of the <code>Window</code> object is
    now defined.

   <li>The <code>embed</code> element is defined to do extension sniffing for
    compatibility with servers that deliver Flash as <code>text/plain</code>.
    (This is marked as an issue in the specification to figure out if there
    is a better way to make this work.)</li>
   <!-- and no, the answer is not to simply break stuff -->

   <li>The <code>embed</code> can now be used without its <code>src</code>
    attribute.

   <li><code>getElementsByClassName()</code> is defined to be ASCII
    case-insensitive in quirks mode for consistency with CSS.

   <li>In HTML documents <code>localName</code> no longer returns the node
    name in uppercase.

   <li><code>data-<var>*</var></code> attributes are defined to be always
    lowercase.

   <li>The <code>opener</code> attribute of the <code>Window</code> object is
    not to be present when the page was opened from a link with
    <code>target="_blank"</code> and <code>rel="noreferrer"</code>.

   <li>The <code>top</code> attribute of the <code>Window</code> object is
    now defined.

   <li>The <code>a</code> element now allows nested flow content, but not
    nested interactive content.

   <li>It is now defined what the <code>header</code> element means to
    document summaries and table of contents.

   <li>What it means to fetch a resource is now defined.

   <li>Patterns are now required for the <code>canvas</code> element.

   <li>The <code>autosubmit</code> attribute has been removed from the
    <code>menu</code> element.

   <li>Support for <code>outerHTML</code> and
    <code>insertAdjacentHTML()</code> has been added.

   <li><code>xml:lang</code> is now allowed in HTML when <code>lang</code> is
    also specified and they have the same value. In XML <code>lang</code> is
    allowed if <code>xml:lang</code> is also specified and they have the same
    value.

   <li>The <code>frameElement</code> attribute of the <code>Window</code>
    object is now defined.

   <li>An event loop and task queue is now defined detailing script execution
    and events. All features have been updated to be defined in terms of this
    mechanism.

   <li>If the <code>alt</code> attribute is omitted a <code>title</code>
    attribute, an enclosing <code>figure</code> element with a
    <code>legend</code> element descendant, or an enclosing section with an
    associated heading must be present.

   <li>The <code>irrelevant</code> attribute has been renamed to
    <code>hidden</code>.

   <li>The <code>definitionURL</code> attribute of MathML is now properly
    supported. Previously it would have ended up being all lowercase during
    parsing.

   <li>User agents must treat US-ASCII as Windows-1252 for compatibility
    reasons.

   <li>An alternative syntax for the DOCTYPE is allowed for compatibility
    with some XML tools.

   <li>Data templates have been removed (consisted of the
    <code>datatemplate</code>, <code>rule</code> and <code>nest</code>
    elements).

   <li>The media elements now support just a single <code>loop</code>
    attribute.

   <li>The <code>load()</code> method on media elements has been redefined as
    asynchronous. It also tries out files in turn now rather than just
    looking at the <code>type</code> attribute of the <code>source</code>
    element.

   <li>A new member called <code>canPlayType()</code> has been added to the
    media elements.

   <li>The <code>totalBytes</code> and <code>bufferedBytes</code> attributes
    have been removed from the media elements.

   <li>The <code>Location</code> object gained a <code>resolveURL()</code>
    method.

   <li>The <code>q</code> element has changed again. Punctuation is to be
    provided by the user agent again.

   <li>Various changes were made to the HTML parser algorithm to be more in
    line with the behavior Web sites require.

   <li>The <code>unload</code> and <code>beforeunload</code> events are now
    defined.

   <li>The IDL blocks in the specification have been revamped to be in line
    with the upcoming Web IDL specification.

   <li>Table headers can now have headers. User agents are required to
    support a <code>headers</code> attribute pointing to a <code>td</code> or
    <code>th</code> element, but authors are required to only let them point
    to <code>th</code> elements.

   <li>Interested parties can now register new <code>http-equiv</code>
    values.

   <li>When the <code>meta</code> element has a <code>charset</code>
    attribute it must occur within the first 512 bytes.

   <li>The <code>StorageEvent</code> object now has a
    <code>storageArea</code> attribute.

   <li>It is now defined how HTML is to be used within the SVG
    <code>foreignObject</code> element.

   <li>The notification API has been dropped.

   <li>How [[Get]] works for the <code>HTMLDocument</code> and
    <code>Window</code> objects is now defined.

   <li>The <code>Window</code> object gained the <code>locationbar</code>,
    <code>menubar</code>, <code>personalbar</code>, <code>scrollbars</code>,
    <code>statusbar</code> and <code>toolbar</code> attributes giving
    information about the user interface.

   <li>The application cache section has been significantly revised and
    updated.

   <li><code>document.domain</code> now relies on the Public Suffix List.
    [<cite><a href="#ref-psl">PSL</a></cite>]

   <li>A non-normative rendering section has been added that describes user
    agent rendering rules for both obsolete and conforming elements.

   <li>A normative section has been added that defines when certain selectors
    as defined in the Selectors and the CSS3 Basic User Interface Module
    match HTML elements. [<cite><a
    href="#ref-selectors">SELECTORS</a></cite>] [<cite><a
    href="#ref-css-ui">CSS-UI</a></cite>]
  </ul>

  <p>Web Forms 2.0, previously a standalone specification, has been fully
   integrated into HTML5 since last publication. The following changes were
   made to the forms chapter:

  <ul>
   <li>Support for XML submission has been removed.

   <li>Support for form filling has been removed.

   <li>Support for filling of the <code>select</code> and
    <code>datalist</code> elements through the <code>data</code> attribute
    has been removed.

   <li>Support for associating a field with multiple forms has been removed.
    A field can still be associated with a form it is not nested in through
    the <code>form</code> attribute.

   <li>The <code>dispatchChangeInput()</code> and
    <code>dispatchFormChange()</code> methods have been removed from the
    <code>select</code>, <code>input</code>, <code>textarea</code>, and
    <code>button</code> elements.

   <li>Repetition templates have been removed.

   <li>The <code>inputmode</code> attribute has been removed.

   <li>The <code>input</code> element in the File Upload state no longer
    supports the <code>min</code> and <code>max</code> attributes.

   <li>The <code>allow</code> attribute on <code>input</code> elements in the
    File Upload state is no longer authoritative.

   <li>The <code>pattern</code> and <code>accept</code> attributes for
    <code>textarea</code> have been removed.

   <li>RFC 3106 is no longer explicitly supported.

   <li>The <code>submit()</code> method now just submits, it no longer
    ensures the form controls are valid.

   <li>The <code>input</code> element in the Range state now defaults to the
    middle, rather than the minimum value.

   <li>The <code>size</code> attribute on the <code>input</code> element is
    now conforming (rather than deprecated).

   <li><code>object</code> elements now partake in form submission.

   <li>The <code>type</code> attribute of the <code>input</code> element
    gained the values <code>color</code> and <code>search</code>.

   <li>The <code>input</code> element gained a <code>multiple</code>
    attribute which allows for either multiple e-mails or multiple files to
    be uploaded depending on the value of the <code>type</code> attribute.

   <li>The <code>input</code>, <code>button</code> and <code>form</code>
    elements now have a <code>novalidate</code> attribute to indicate that
    the form fields should not be required to have valid values upon
    submission.

   <li>When the <code>label</code> element contains an <code>input</code> it
    may still have a <code>for</code> attribute as long as it points to the
    <code>input</code> element it contains.

   <li>The <code>input</code> element now has an <code>indeterminate</code>
    IDL attribute.

   <li>The <code>input</code> element gained a <code>placeholder</code>
    attribute.
  </ul>

  <h3 id=changes-2008-01-22><span class=secno>5.10. </span>Changes from 22
   January 2008 to 10 June 2008</h3>

  <ul>
   <li>Implementation and authoring details around the <code>ping</code>
    attribute have changed.

   <li><code>&lt;meta http-equiv=content-type></code> is now a conforming way
    to set the character encoding.

   <li>API for the <code>canvas</code> element has been cleaned up. Text
    support has been added.

   <li><code>globalStorage</code> is now restricted to the same-origin policy
    and renamed to <code>localStorage</code>. Related event dispatching has
    been clarified.

   <li><code>postMessage()</code> API changed. Only the origin of the message
    is exposed, no longer the URL. It also requires a second argument that
    indicates the origin of the target document.

   <li>Drag and drop API has got clarification. The <code>dataTransfer</code>
    object now has a <code>types</code> attribute indicating the type of data
    being transferred.

   <li>The <code>m</code> element is now called <code>mark</code>.

   <li>Server-sent events has changed and gotten clarification. It uses a new
    format so that older implementations are not broken.

   <li>The <code>figure</code> element no longer requires a caption.

   <li>The <code>ol</code> element has a new <code>reversed</code> attribute.


   <li>Character encoding detection has changed in response to feedback.

   <li>Various changes have been made to the HTML parser section in response
    to implementation feedback.

   <li>Various changes to the editing section have been made, including
    adding <code>queryCommandEnabled()</code> and related methods.

   <li>The <code>headers</code> attribute has been added for <code>td</code>
    elements.

   <li>The <code>table</code> element has a new <code>createTBody()</code>
    method.

   <li>MathML support has been added to the HTML parser section. (SVG support
    is still awaiting input from the SVG WG.)

   <li>Author-defined attributes have been added. Authors can add attributes
    to elements in the form of <code>data-<var>name</var></code> and can
    access these through the DOM using <code>dataset[<var>name</var>]</code>
    on the element in question.

   <li>The <code>q</code> element has changed to require punctuation inside
    rather than having the browser render it.

   <li>The <code>target</code> attribute can now have the value
    <code>_blank</code>.

   <li>The <code>showModalDialog</code> API has been added.

   <li>The <code>document.domain</code> API has been defined.

   <li>The <code>source</code> element now has a new <code>pixelratio</code>
    attribute useful for videos that have some kind encoding error.

   <li><code>bufferedBytes</code>, <code>totalBytes</code> and
    <code>bufferingThrottled</code> IDL attributes have been added to the
    <code>video</code> element.

   <li>Media <code>begin</code> event has been renamed to
    <code>loadstart</code> for consistency with the Progress Events
    specification.

   <li><code>charset</code> attribute has been added to <code>script</code>.

   <li>The <code>iframe</code> element has gained the <code>sandbox</code>
    and <code>seamless</code> attributes which provide sandboxing
    functionality.

   <li>The <code>ruby</code>, <code>rt</code> and <code>rp</code> elements
    have been added to support ruby annotation.

   <li>A <code>showNotification()</code> method has been added to show
    notification messages to the user.

   <li>Support for <code>beforeprint</code> and <code>afterprint</code>
    events has been added.
  </ul>

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

  <p>The editors would like to thank Ben Millard, Bruce Lawson, Cameron
   McCormack, Charles McCathieNevile, Dan Connolly, David
   H&aring;s&auml;ther, Dennis German, Frank Ellermann, Frank Palinkas,
   Futomi Hatano<!-- 羽田野太巳 -->, Gordon P. Hemsley, Henri Sivonen,
   James Graham, Jens Meiert, Jeremy Keith, J&uuml;rgen Jeka, Krijn Hoetmer,
   Leif Halvard Silli, Maciej Stachowiak, Marcos Caceres, Mark Pilgrim,
   Martijn Wargers, Martyn Haigh, Masataka Yakura, Michael Smith,
   <i>Ms2ger</i>, Olivier Gendrin, &Oslash;istein E. Andersen, Philip
   J&auml;genstedt, Philip Taylor, Randy Peterman, Toby Inkster, and Yngve
   Spjeld Landro for their contributions to this document as well as to all
   the people who have contributed to HTML5 over the years for improving the
   Web!

  <h2 class=no-num id=references>References</h2>

  <dl><!--<dt>[<dfn id="ref-cors">CORS</dfn>]</dt>

      <dd><cite><a href="http://www.w3.org/TR/cors/">Cross-Origin Resource Sharing</a></cite>, A. van Kesteren. W3C.</dd>-->

   <dt>[<dfn id=ref-css-ui>CSS-UI</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/css3-ui/">CSS3 Basic User
    Interface Module</a></cite>, T. &Ccedil;elik. W3C.

   <dt>[<dfn id=ref-doctype>DOCTYPE</dfn>]

   <dd><cite><a href="http://hsivonen.iki.fi/doctype/">Activating Browser
    Modes with Doctype</a></cite>, H. Sivonen.

   <dt>[<dfn id=ref-dom2html>DOM2HTML</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/DOM-Level-2-HTML/">Document Object
    Model (DOM) Level 2 HTML Specification</a></cite>, J. Stenback, P. Le
    H&eacute;garet, A. Le Hors. W3C.

   <dt>[<dfn id=ref-html4>HTML4</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/html4/">HTML 4.01
    Specification</a></cite>, D. Raggett, A. Le Hors, I. Jacobs, editors.
    W3C.

   <dt>[<dfn id=ref-html5>HTML5</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/html5/">HTML5</a></cite>, I.
    Hickson. W3C.

   <dd><cite><a
    href="http://www.whatwg.org/specs/web-apps/current-work/">HTML5</a></cite>
    (editor's draft), I. Hickson. WHATWG.

   <dd><cite><a href="http://dev.w3.org/html5/spec/">HTML5</a></cite>
    (editor's draft), I. Hickson. W3C.

   <dt>[<dfn id=ref-psl>PSL</dfn>]

   <dd><cite><a href="http://publicsuffix.org/">Public Suffix
    List</a></cite>, Mozilla Foundation.

   <dt>[<dfn id=ref-selectors>SELECTORS</dfn>]

   <dd><cite><a
    href="http://www.w3.org/TR/css3-selectors/">Selectors</a></cite>, D.
    Glazman, T. &Ccedil;elik, I. Hickson. W3C.

   <dt>[<dfn id=ref-xhtml1>XHTML1</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/xhtml11/">XHTML&trade; 1.1 -
    Module-based XHTML (Second Edition)</a></cite>, S. McCarron, M. Ishikawa.
    W3C.

   <dt>[<dfn id=ref-xml>XML</dfn>]

   <dd><cite><a href="http://www.w3.org/TR/xml/">Extensible Markup Language
    (XML) 1.0 (Fifth Edition)</a></cite>, T. Bray, J. Paoli, C.
    Sperberg-McQueen, E. Maler, F. Yergeau. W3C.

   <dd><cite><a href="http://www.w3.org/TR/xml-names/">Namespaces in XML 1.0
    (Third Edition)</a></cite>, T. Bray, D. Hollander, A. Layman, R. Tobin,
    H. S. Thompson. W3C.
  </dl>