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content-models.html 118 KB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en-US-x-Hixie" ><head><title>3.2.5 Content models &#8212; HTML5 </title><style type="text/css">
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     -webkit-column-gap: 1em;
   }
   #named-character-references-table > table > tbody > tr > td:first-child + td,
   #named-character-references-table > table > tbody > tr > td:last-child { text-align: center; }
   #named-character-references-table > table > tbody > tr > td:last-child:hover > span { position: absolute; top: auto; left: auto; margin-left: 0.5em; line-height: 1.2; font-size: 5em; border: outset; padding: 0.25em 0.5em; background: white; width: 1.25em; height: auto; text-align: center; }
   #named-character-references-table > table > tbody > tr#entity-CounterClockwiseContourIntegral > td:first-child { font-size: 0.5em; }

   .glyph.control { color: red; }

   @font-face {
     font-family: 'Essays1743';
     src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743.ttf');
   }
   @font-face {
     font-family: 'Essays1743';
     font-weight: bold;
     src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Bold.ttf');
   }
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     font-family: 'Essays1743';
     font-style: italic;
     src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-Italic.ttf');
   }
   @font-face {
     font-family: 'Essays1743';
     font-style: italic;
     font-weight: bold;
     src: url('http://www.whatwg.org/specs/web-apps/current-work/fonts/Essays1743-BoldItalic.ttf');
   }

  </style><style type="text/css">
   .domintro:before { display: table; margin: -1em -0.5em -0.5em auto; width: auto; content: 'This box is non-normative. Implementation requirements are given below this box.'; color: black; font-style: italic; border: solid 2px; background: white; padding: 0 0.25em; }
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  </head><body><div class="head" id="head">
<div id="multipage-common">
  <p class="stability" id="wip"><strong>This is a work in
  progress!</strong> For the latest updates from the HTML WG, possibly
  including important bug fixes, please look at the <a href="http://dev.w3.org/html5/spec/Overview.html">editor's draft</a> instead.
  There may also be a more
  <a href="http://www.w3.org/TR/html5">up-to-date Working Draft</a>
   with changes based on resolution of Last Call issues.
  <input onclick="closeWarning(this.parentNode)" type="button" value="&#9587;&#8413;"></p>
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   <p><a href="http://www.w3.org/"><img alt="W3C" height="48" src="http://www.w3.org/Icons/w3c_home" width="72"></a></p>

   <h1>HTML5</h1>
   </div><div>
   <a href="elements.html" class="prev">3.2 Elements</a> &#8211;
   <a href="spec.html#contents">Table of contents</a> &#8211;
   <a href="apis-in-html-documents.html" class="next">3.3 APIs in HTML documents</a>
  <ol class="toc"><li><ol><li><ol><li><a href="content-models.html#content-models"><span class="secno">3.2.5 </span>Content models</a>
      <ol><li><a href="content-models.html#kinds-of-content"><span class="secno">3.2.5.1 </span>Kinds of content</a>
        <ol><li><a href="content-models.html#metadata-content-0"><span class="secno">3.2.5.1.1 </span>Metadata content</a></li><li><a href="content-models.html#flow-content-0"><span class="secno">3.2.5.1.2 </span>Flow content</a></li><li><a href="content-models.html#sectioning-content-0"><span class="secno">3.2.5.1.3 </span>Sectioning content</a></li><li><a href="content-models.html#heading-content-0"><span class="secno">3.2.5.1.4 </span>Heading content</a></li><li><a href="content-models.html#phrasing-content-0"><span class="secno">3.2.5.1.5 </span>Phrasing content</a></li><li><a href="content-models.html#embedded-content-0"><span class="secno">3.2.5.1.6 </span>Embedded content</a></li><li><a href="content-models.html#interactive-content-0"><span class="secno">3.2.5.1.7 </span>Interactive content</a></li></ol></li><li><a href="content-models.html#transparent-content-models"><span class="secno">3.2.5.2 </span>Transparent content models</a></li><li><a href="content-models.html#paragraphs"><span class="secno">3.2.5.3 </span>Paragraphs</a></li></ol></li><li><a href="content-models.html#requirements-relating-to-bidirectional-algorithm-formatting-characters"><span class="secno">3.2.6 </span>Requirements relating to bidirectional-algorithm formatting
  characters</a></li><li><a href="content-models.html#wai-aria"><span class="secno">3.2.7 </span>WAI-ARIA</a></li></ol></li></ol></li></ol></div>

  <h4 id="content-models"><span class="secno">3.2.5 </span><dfn>Content models</dfn></h4><p>Each element defined in this specification has a content model: a
  description of the element's expected contents. An <a href="infrastructure.html#html-elements" title="HTML
  elements">HTML element</a> must have contents that match the
  requirements described in the element's content model.</p><p class="note">As noted in the conformance and terminology
  sections, for the purposes of determining if an element matches its
  content model or not, <a href="infrastructure.html#text-node" title="text
  node"><code>CDATASection</code> nodes in the DOM are treated as
  equivalent to <code>Text</code> nodes</a>, and <a href="infrastructure.html#entity-references">entity reference nodes are treated as if
  they were expanded in place</a>.</p><p>The <a href="common-microsyntaxes.html#space-character" title="space character">space characters</a> are
  always allowed between elements. User agents represent these
  characters between elements in the source markup as text nodes in
  the DOM. Empty <a href="infrastructure.html#text-node" title="text node">text nodes</a> and <a href="infrastructure.html#text-node" title="text node">text nodes</a> consisting of just sequences of
  those characters are considered <dfn id="inter-element-whitespace">inter-element
  whitespace</dfn>.</p><p><a href="#inter-element-whitespace">Inter-element whitespace</a>, comment nodes, and
  processing instruction nodes must be ignored when establishing
  whether an element's contents match the element's content model or
  not, and must be ignored when following algorithms that define
  document and element semantics.</p><p class="note">Thus, an element <var title="">A</var> is said to be
  <i>preceded or followed</i> by a second element <var title="">B</var> if <var title="">A</var> and <var title="">B</var>
  have the same parent node and there are no other element nodes or
  text nodes (other than <a href="#inter-element-whitespace">inter-element whitespace</a>)
  between them. Similarly, a node is the <i>only child</i> of an
  element if that element contains no other nodes other than
  <a href="#inter-element-whitespace">inter-element whitespace</a>, comment nodes, and processing
  instruction nodes.</p><p>Authors must not use <a href="infrastructure.html#html-elements">HTML elements</a> anywhere except
  where they are explicitly allowed, as defined for each element, or
  as explicitly required by other specifications. For XML compound
  documents, these contexts could be inside elements from other
  namespaces, if those elements are defined as providing the relevant
  contexts.</p><div class="example">
   <p>For example, the Atom specification defines a <code title="">content</code> element. When its <code title="">type</code> attribute has the value <code title="">xhtml</code>, the Atom specification requires that it
   contain a single HTML <code><a href="grouping-content.html#the-div-element">div</a></code> element. Thus, a
   <code><a href="grouping-content.html#the-div-element">div</a></code> element is allowed in that context, even though
   this is not explicitly normatively stated by this specification. <a href="references.html#refsATOM">[ATOM]</a></p>
  </div><p>In addition, <a href="infrastructure.html#html-elements">HTML elements</a> may be orphan nodes
  (i.e. without a parent node).</p><div class="example">

   <p>For example, creating a <code><a href="tabular-data.html#the-td-element">td</a></code> element and storing it
   in a global variable in a script is conforming, even though
   <code><a href="tabular-data.html#the-td-element">td</a></code> elements are otherwise only supposed to be used
   inside <code><a href="tabular-data.html#the-tr-element">tr</a></code> elements.</p>

   <pre>var data = {
  name: "Banana",
  cell: document.createElement('td'),
};</pre>

  </div><h5 id="kinds-of-content"><span class="secno">3.2.5.1 </span>Kinds of content</h5><p>Each element in HTML falls into zero or more <dfn id="content-categories" title="content
  categories">categories</dfn> that group elements with similar
  characteristics together. The following broad categories are used in
  this specification:</p><ul class="brief"><li><a href="#metadata-content">Metadata content</a></li>
   <li><a href="#flow-content">Flow content</a></li>
   <li><a href="#sectioning-content">Sectioning content</a></li>
   <li><a href="#heading-content">Heading content</a></li>
   <li><a href="#phrasing-content">Phrasing content</a></li>
   <li><a href="#embedded-content">Embedded content</a></li>
   <li><a href="#interactive-content">Interactive content</a></li>
  </ul><p class="note">Some elements also fall into other categories, which
  are defined in other parts of this specification.</p><p>These categories are related as follows:</p><p><object data="images/content-venn.svg" height="288" width="1000"><img alt="Sectioning content, heading content, phrasing content, and
  embedded content are all types of flow content. Embedded content is
  also a type of phrasing content." src="content-venn.png"></object></p><p>In addition, certain elements are categorized as <a href="forms.html#form-associated-element" title="form-associated element">form-associated elements</a> and
  further subcategorized to define their role in various form-related
  processing models.</p><p>Some elements have unique requirements and do not fit into any
  particular category.</p><h6 id="metadata-content-0"><span class="secno">3.2.5.1.1 </span>Metadata content</h6><p><dfn id="metadata-content">Metadata content</dfn> is content that sets up the
  presentation or behavior of the rest of the content, or that sets
  up the relationship of the document with other documents, or that
  conveys other "out of band" information.</p><ul class="brief category-list"><li><code><a href="semantics.html#the-base-element">base</a></code></li>
   <li><code><a href="interactive-elements.html#the-command-element">command</a></code></li>
   <li><code><a href="semantics.html#the-link-element">link</a></code></li>
   <li><code><a href="semantics.html#the-meta-element">meta</a></code></li>
   <li><code><a href="scripting-1.html#the-noscript-element">noscript</a></code></li>
   <li><code><a href="scripting-1.html#the-script-element">script</a></code></li>
   <li><code><a href="semantics.html#the-style-element">style</a></code></li>
   <li><code><a href="semantics.html#the-title-element">title</a></code></li>
  </ul><p>Elements from other namespaces whose semantics are primarily
  metadata-related (e.g. RDF) are also <a href="#metadata-content">metadata
  content</a>.</p><div class="example">

   <p>Thus, in the XML serialization, one can use RDF, like this:</p>

   <pre>&lt;html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:r="http://www.w3.org/1999/02/22-rdf-syntax-ns#"&gt;
 &lt;head&gt;
  &lt;title&gt;Hedral's Home Page&lt;/title&gt;
  &lt;r:RDF&gt;
   &lt;Person xmlns="http://www.w3.org/2000/10/swap/pim/contact#"
           r:about="http://hedral.example.com/#"&gt;
    &lt;fullName&gt;Cat Hedral&lt;/fullName&gt;
    &lt;mailbox r:resource="mailto:hedral@damowmow.com"/&gt;
    &lt;personalTitle&gt;Sir&lt;/personalTitle&gt;
   &lt;/Person&gt;
  &lt;/r:RDF&gt;
 &lt;/head&gt;
 &lt;body&gt;
  &lt;h1&gt;My home page&lt;/h1&gt;
  &lt;p&gt;I like playing with string, I guess. Sister says squirrels are fun
  too so sometimes I follow her to play with them.&lt;/p&gt;
 &lt;/body&gt;
&lt;/html&gt;</pre>

   <p>This isn't possible in the HTML serialization, however.</p>

  </div><h6 id="flow-content-0"><span class="secno">3.2.5.1.2 </span>Flow content</h6><p>Most elements that are used in the body of documents and
  applications are categorized as <dfn id="flow-content">flow content</dfn>.</p><ul class="brief category-list"><li><code><a href="text-level-semantics.html#the-a-element">a</a></code></li>
   <li><code><a href="text-level-semantics.html#the-abbr-element">abbr</a></code></li>
   <li><code><a href="sections.html#the-address-element">address</a></code></li>
   <li><code><a href="the-map-element.html#the-area-element">area</a></code> (if it is a descendant of a <code><a href="the-map-element.html#the-map-element">map</a></code> element)</li>
   <li><code><a href="sections.html#the-article-element">article</a></code></li>
   <li><code><a href="sections.html#the-aside-element">aside</a></code></li>
   <li><code><a href="the-iframe-element.html#the-audio-element">audio</a></code></li>
   <li><code><a href="text-level-semantics.html#the-b-element">b</a></code></li>
   <li><code><a href="text-level-semantics.html#the-bdi-element">bdi</a></code></li>
   <li><code><a href="text-level-semantics.html#the-bdo-element">bdo</a></code></li>
   <li><code><a href="grouping-content.html#the-blockquote-element">blockquote</a></code></li>
   <li><code><a href="text-level-semantics.html#the-br-element">br</a></code></li>
   <li><code><a href="the-button-element.html#the-button-element">button</a></code></li>
   <li><code><a href="the-canvas-element.html#the-canvas-element">canvas</a></code></li>
   <li><code><a href="text-level-semantics.html#the-cite-element">cite</a></code></li>
   <li><code><a href="text-level-semantics.html#the-code-element">code</a></code></li>
   <li><code><a href="interactive-elements.html#the-command-element">command</a></code></li>
   <li><code><a href="the-button-element.html#the-datalist-element">datalist</a></code></li>
   <li><code><a href="edits.html#the-del-element">del</a></code></li>
   <li><code><a href="interactive-elements.html#the-details-element">details</a></code></li>
   <li><code><a href="text-level-semantics.html#the-dfn-element">dfn</a></code></li>
   <li><code><a href="grouping-content.html#the-div-element">div</a></code></li>
   <li><code><a href="grouping-content.html#the-dl-element">dl</a></code></li>
   <li><code><a href="text-level-semantics.html#the-em-element">em</a></code></li>
   <li><code><a href="the-iframe-element.html#the-embed-element">embed</a></code></li>
   <li><code><a href="forms.html#the-fieldset-element">fieldset</a></code></li>
   <li><code><a href="grouping-content.html#the-figure-element">figure</a></code></li>
   <li><code><a href="sections.html#the-footer-element">footer</a></code></li>
   <li><code><a href="forms.html#the-form-element">form</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h1</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h2</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h3</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h4</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h5</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h6</a></code></li>
   <li><code><a href="sections.html#the-header-element">header</a></code></li>
   <li><code><a href="sections.html#the-hgroup-element">hgroup</a></code></li>
   <li><code><a href="grouping-content.html#the-hr-element">hr</a></code></li>
   <li><code><a href="text-level-semantics.html#the-i-element">i</a></code></li>
   <li><code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code></li>
   <li><code><a href="embedded-content-1.html#the-img-element">img</a></code></li>
   <li><code><a href="the-input-element.html#the-input-element">input</a></code></li>
   <li><code><a href="edits.html#the-ins-element">ins</a></code></li>
   <li><code><a href="text-level-semantics.html#the-kbd-element">kbd</a></code></li>
   <li><code><a href="the-button-element.html#the-keygen-element">keygen</a></code></li>
   <li><code><a href="forms.html#the-label-element">label</a></code></li>
   <li><code><a href="the-map-element.html#the-map-element">map</a></code></li>
   <li><code><a href="text-level-semantics.html#the-mark-element">mark</a></code></li>
   <li><code><a href="the-map-element.html#math">math</a></code></li>
   <li><code><a href="interactive-elements.html#the-menu-element">menu</a></code></li>
   <li><code><a href="the-button-element.html#the-meter-element">meter</a></code></li>
   <li><code><a href="sections.html#the-nav-element">nav</a></code></li>
   <li><code><a href="scripting-1.html#the-noscript-element">noscript</a></code></li>
   <li><code><a href="the-iframe-element.html#the-object-element">object</a></code></li>
   <li><code><a href="grouping-content.html#the-ol-element">ol</a></code></li>
   <li><code><a href="the-button-element.html#the-output-element">output</a></code></li>
   <li><code><a href="grouping-content.html#the-p-element">p</a></code></li>
   <li><code><a href="grouping-content.html#the-pre-element">pre</a></code></li>
   <li><code><a href="the-button-element.html#the-progress-element">progress</a></code></li>
   <li><code><a href="text-level-semantics.html#the-q-element">q</a></code></li>
   <li><code><a href="text-level-semantics.html#the-ruby-element">ruby</a></code></li>
   <li><code><a href="text-level-semantics.html#the-s-element">s</a></code></li>
   <li><code><a href="text-level-semantics.html#the-samp-element">samp</a></code></li>
   <li><code><a href="scripting-1.html#the-script-element">script</a></code></li>
   <li><code><a href="sections.html#the-section-element">section</a></code></li>
   <li><code><a href="the-button-element.html#the-select-element">select</a></code></li>
   <li><code><a href="text-level-semantics.html#the-small-element">small</a></code></li>
   <li><code><a href="text-level-semantics.html#the-span-element">span</a></code></li>
   <li><code><a href="text-level-semantics.html#the-strong-element">strong</a></code></li>
   <li><code><a href="semantics.html#the-style-element">style</a></code> (if the <code title="attr-style-scoped"><a href="semantics.html#attr-style-scoped">scoped</a></code> attribute is present)</li>
   <li><code><a href="text-level-semantics.html#the-sub-and-sup-elements">sub</a></code></li>
   <li><code><a href="text-level-semantics.html#the-sub-and-sup-elements">sup</a></code></li>
   <li><code><a href="the-map-element.html#svg">svg</a></code></li>
   <li><code><a href="tabular-data.html#the-table-element">table</a></code></li>
   <li><code><a href="the-button-element.html#the-textarea-element">textarea</a></code></li>
   <li><code><a href="text-level-semantics.html#the-time-element">time</a></code></li>
   <li><code><a href="text-level-semantics.html#the-u-element">u</a></code></li>
   <li><code><a href="grouping-content.html#the-ul-element">ul</a></code></li>
   <li><code><a href="text-level-semantics.html#the-var-element">var</a></code></li>
   <li><code><a href="the-iframe-element.html#the-video-element">video</a></code></li>
   <li><code><a href="text-level-semantics.html#the-wbr-element">wbr</a></code></li>
   <li><a href="#text-content" title="text content">Text</a></li>
  </ul><p>As a general rule, elements whose content model allows any
  <a href="#flow-content">flow content</a> should have either at least one descendant
  <a href="infrastructure.html#text-node">text node</a> that is not <a href="#inter-element-whitespace">inter-element
  whitespace</a>, or at least one descendant element node that is
  <a href="#embedded-content">embedded content</a>. For the purposes of this requirement,
  <code><a href="edits.html#the-del-element">del</a></code> elements and their descendants must not be counted
  as contributing to the ancestors of the <code><a href="edits.html#the-del-element">del</a></code>
  element.</p><p>This requirement is not a hard requirement, however, as there are
  many cases where an element can be empty legitimately, for example
  when it is used as a placeholder which will later be filled in by a
  script, or when the element is part of a template and would on most
  pages be filled in but on some pages is not relevant.</p><h6 id="sectioning-content-0"><span class="secno">3.2.5.1.3 </span>Sectioning content</h6><p><dfn id="sectioning-content">Sectioning content</dfn> is content that defines the scope
  of <a href="#heading-content" title="heading content">headings</a> and <a href="sections.html#the-footer-element" title="footer">footers</a>.</p><ul class="brief category-list"><li><code><a href="sections.html#the-article-element">article</a></code></li>
   <li><code><a href="sections.html#the-aside-element">aside</a></code></li>
   <li><code><a href="sections.html#the-nav-element">nav</a></code></li>
   <li><code><a href="sections.html#the-section-element">section</a></code></li>
  </ul><p>Each <a href="#sectioning-content">sectioning content</a> element potentially has a
  heading and an <a href="sections.html#outline">outline</a>. See the section on
  <a href="sections.html#headings-and-sections">headings and sections</a> for further details.</p><p class="note">There are also certain elements that are <a href="sections.html#sectioning-root" title="sectioning root">sectioning roots</a>. These are distinct
  from <a href="#sectioning-content">sectioning content</a>, but they can also have an
  <a href="sections.html#outline">outline</a>.</p><h6 id="heading-content-0"><span class="secno">3.2.5.1.4 </span>Heading content</h6><p><dfn id="heading-content">Heading content</dfn> defines the header of a section
  (whether explicitly marked up using <a href="#sectioning-content">sectioning content</a>
  elements, or implied by the heading content itself).</p><ul class="brief category-list"><li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h1</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h2</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h3</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h4</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h5</a></code></li>
   <li><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h6</a></code></li>
   <li><code><a href="sections.html#the-hgroup-element">hgroup</a></code></li>
  </ul><h6 id="phrasing-content-0"><span class="secno">3.2.5.1.5 </span>Phrasing content</h6><p><dfn id="phrasing-content">Phrasing content</dfn> is the text of the document, as well
  as elements that mark up that text at the intra-paragraph
  level. Runs of <a href="#phrasing-content">phrasing content</a> form <a href="#paragraph" title="paragraph">paragraphs</a>.</p><ul class="brief category-list"><li><code><a href="text-level-semantics.html#the-a-element">a</a></code> (if it contains only <a href="#phrasing-content">phrasing content</a>)</li>
   <li><code><a href="text-level-semantics.html#the-abbr-element">abbr</a></code></li>
   <li><code><a href="the-map-element.html#the-area-element">area</a></code> (if it is a descendant of a <code><a href="the-map-element.html#the-map-element">map</a></code> element)</li>
   <li><code><a href="the-iframe-element.html#the-audio-element">audio</a></code></li>
   <li><code><a href="text-level-semantics.html#the-b-element">b</a></code></li>
   <li><code><a href="text-level-semantics.html#the-bdi-element">bdi</a></code></li>
   <li><code><a href="text-level-semantics.html#the-bdo-element">bdo</a></code></li>
   <li><code><a href="text-level-semantics.html#the-br-element">br</a></code></li>
   <li><code><a href="the-button-element.html#the-button-element">button</a></code></li>
   <li><code><a href="the-canvas-element.html#the-canvas-element">canvas</a></code></li>
   <li><code><a href="text-level-semantics.html#the-cite-element">cite</a></code></li>
   <li><code><a href="text-level-semantics.html#the-code-element">code</a></code></li>
   <li><code><a href="interactive-elements.html#the-command-element">command</a></code></li>
   <li><code><a href="the-button-element.html#the-datalist-element">datalist</a></code></li>
   <li><code><a href="edits.html#the-del-element">del</a></code> (if it contains only <a href="#phrasing-content">phrasing content</a>)</li>
   <li><code><a href="text-level-semantics.html#the-dfn-element">dfn</a></code></li>
   <li><code><a href="text-level-semantics.html#the-em-element">em</a></code></li>
   <li><code><a href="the-iframe-element.html#the-embed-element">embed</a></code></li>
   <li><code><a href="text-level-semantics.html#the-i-element">i</a></code></li>
   <li><code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code></li>
   <li><code><a href="embedded-content-1.html#the-img-element">img</a></code></li>
   <li><code><a href="the-input-element.html#the-input-element">input</a></code></li>
   <li><code><a href="edits.html#the-ins-element">ins</a></code> (if it contains only <a href="#phrasing-content">phrasing content</a>)</li>
   <li><code><a href="text-level-semantics.html#the-kbd-element">kbd</a></code></li>
   <li><code><a href="the-button-element.html#the-keygen-element">keygen</a></code></li>
   <li><code><a href="forms.html#the-label-element">label</a></code></li>
   <li><code><a href="the-map-element.html#the-map-element">map</a></code> (if it contains only <a href="#phrasing-content">phrasing content</a>)</li>
   <li><code><a href="text-level-semantics.html#the-mark-element">mark</a></code></li>
   <li><code><a href="the-map-element.html#math">math</a></code></li>
   <li><code><a href="the-button-element.html#the-meter-element">meter</a></code></li>
   <li><code><a href="scripting-1.html#the-noscript-element">noscript</a></code></li>
   <li><code><a href="the-iframe-element.html#the-object-element">object</a></code></li>
   <li><code><a href="the-button-element.html#the-output-element">output</a></code></li>
   <li><code><a href="the-button-element.html#the-progress-element">progress</a></code></li>
   <li><code><a href="text-level-semantics.html#the-q-element">q</a></code></li>
   <li><code><a href="text-level-semantics.html#the-ruby-element">ruby</a></code></li>
   <li><code><a href="text-level-semantics.html#the-s-element">s</a></code></li>
   <li><code><a href="text-level-semantics.html#the-samp-element">samp</a></code></li>
   <li><code><a href="scripting-1.html#the-script-element">script</a></code></li>
   <li><code><a href="the-button-element.html#the-select-element">select</a></code></li>
   <li><code><a href="text-level-semantics.html#the-small-element">small</a></code></li>
   <li><code><a href="text-level-semantics.html#the-span-element">span</a></code></li>
   <li><code><a href="text-level-semantics.html#the-strong-element">strong</a></code></li>
   <li><code><a href="text-level-semantics.html#the-sub-and-sup-elements">sub</a></code></li>
   <li><code><a href="text-level-semantics.html#the-sub-and-sup-elements">sup</a></code></li>
   <li><code><a href="the-map-element.html#svg">svg</a></code></li>
   <li><code><a href="the-button-element.html#the-textarea-element">textarea</a></code></li>
   <li><code><a href="text-level-semantics.html#the-time-element">time</a></code></li>
   <li><code><a href="text-level-semantics.html#the-u-element">u</a></code></li>
   <li><code><a href="text-level-semantics.html#the-var-element">var</a></code></li>
   <li><code><a href="the-iframe-element.html#the-video-element">video</a></code></li>
   <li><code><a href="text-level-semantics.html#the-wbr-element">wbr</a></code></li>
   <li><a href="#text-content" title="text content">Text</a></li>
  </ul><p>As a general rule, elements whose content model allows any
  <a href="#phrasing-content">phrasing content</a> should have either at least one
  descendant <a href="infrastructure.html#text-node">text node</a> that is not <a href="#inter-element-whitespace">inter-element
  whitespace</a>, or at least one descendant element node that is
  <a href="#embedded-content">embedded content</a>. For the purposes of this requirement,
  nodes that are descendants of <code><a href="edits.html#the-del-element">del</a></code> elements must not be
  counted as contributing to the ancestors of the <code><a href="edits.html#the-del-element">del</a></code>
  element.</p><p class="note">Most elements that are categorized as phrasing
  content can only contain elements that are themselves categorized as
  phrasing content, not any flow content.</p><p><dfn id="text-content" title="text content">Text</dfn>, in the context of content
  models, means <a href="infrastructure.html#text-node" title="text node">text nodes</a>. <a href="#text-content" title="text content">Text</a> is sometimes used as a content
  model on its own, but is also <a href="#phrasing-content">phrasing content</a>, and can
  be <a href="#inter-element-whitespace">inter-element whitespace</a> (if the <a href="infrastructure.html#text-node" title="text
  node">text nodes</a> are empty or contain just <a href="common-microsyntaxes.html#space-character" title="space
  character">space characters</a>).</p><h6 id="embedded-content-0"><span class="secno">3.2.5.1.6 </span>Embedded content</h6><p><dfn id="embedded-content">Embedded content</dfn> is content that imports another
  resource into the document, or content from another vocabulary that
  is inserted into the document.</p><ul class="brief category-list"><li><code><a href="the-iframe-element.html#the-audio-element">audio</a></code></li>
   <li><code><a href="the-canvas-element.html#the-canvas-element">canvas</a></code></li>
   <li><code><a href="the-iframe-element.html#the-embed-element">embed</a></code></li>
   <li><code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code></li>
   <li><code><a href="embedded-content-1.html#the-img-element">img</a></code></li>
   <li><code><a href="the-map-element.html#math">math</a></code></li>
   <li><code><a href="the-iframe-element.html#the-object-element">object</a></code></li>
   <li><code><a href="the-map-element.html#svg">svg</a></code></li>
   <li><code><a href="the-iframe-element.html#the-video-element">video</a></code></li>
  </ul><p>Elements that are from namespaces other than the <a href="namespaces.html#html-namespace-0">HTML
  namespace</a> and that convey content but not metadata, are
  <a href="#embedded-content">embedded content</a> for the purposes of the content models
  defined in this specification. (For example, MathML, or SVG.)</p><p>Some embedded content elements can have <dfn id="fallback-content">fallback
  content</dfn>: content that is to be used when the external resource
  cannot be used (e.g. because it is of an unsupported format). The
  element definitions state what the fallback is, if any.</p><h6 id="interactive-content-0"><span class="secno">3.2.5.1.7 </span>Interactive content</h6><p><dfn id="interactive-content">Interactive content</dfn> is content that is specifically
  intended for user interaction.</p><ul class="brief category-list"><li><code><a href="text-level-semantics.html#the-a-element">a</a></code></li>
   <li><code><a href="the-iframe-element.html#the-audio-element">audio</a></code> (if the <code title="attr-media-controls"><a href="the-iframe-element.html#attr-media-controls">controls</a></code> attribute is present)</li>
   <li><code><a href="the-button-element.html#the-button-element">button</a></code></li>
   <li><code><a href="interactive-elements.html#the-details-element">details</a></code></li>
   <li><code><a href="the-iframe-element.html#the-embed-element">embed</a></code></li>
   <li><code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code></li>
   <li><code><a href="embedded-content-1.html#the-img-element">img</a></code> (if the <code title="attr-hyperlink-usemap"><a href="the-map-element.html#attr-hyperlink-usemap">usemap</a></code> attribute is present)</li>
   <li><code><a href="the-input-element.html#the-input-element">input</a></code> (if the <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute is <em>not</em> in the <a href="states-of-the-type-attribute.html#hidden-state" title="attr-input-type-hidden">Hidden</a> state)</li>
   <li><code><a href="the-button-element.html#the-keygen-element">keygen</a></code></li>
   <li><code><a href="forms.html#the-label-element">label</a></code></li>
   <li><code><a href="interactive-elements.html#the-menu-element">menu</a></code> (if the <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute is in the <a href="interactive-elements.html#toolbar-state" title="toolbar state">toolbar</a> state)</li>
   <li><code><a href="the-iframe-element.html#the-object-element">object</a></code> (if the <code title="attr-hyperlink-usemap"><a href="the-map-element.html#attr-hyperlink-usemap">usemap</a></code> attribute is present)</li>
   <li><code><a href="the-button-element.html#the-select-element">select</a></code></li>
   <li><code><a href="the-button-element.html#the-textarea-element">textarea</a></code></li>
   <li><code><a href="the-iframe-element.html#the-video-element">video</a></code> (if the <code title="attr-media-controls"><a href="the-iframe-element.html#attr-media-controls">controls</a></code> attribute is present)</li>
  </ul><p>Certain elements in HTML have an <a href="#activation-behavior">activation
  behavior</a>, which means that the user can activate them. This
  triggers a sequence of events dependent on the activation mechanism,
  and normally culminating in a <code title="event-click"><a href="infrastructure.html#event-click">click</a></code>
  event<span class="impl">, as described below</span>.</p><div class="impl">

  <p>The user agent should allow the user to manually trigger elements
  that have an <a href="#activation-behavior">activation behavior</a>, for instance using
  keyboard or voice input, or through mouse clicks. When the user
  triggers an element with a defined <a href="#activation-behavior">activation behavior</a>
  in a manner other than clicking it, the default action of the
  interaction event must be to <a href="#run-synthetic-click-activation-steps">run synthetic click activation
  steps</a> on the element.</p> 

  <p>When a user agent is to <dfn id="run-synthetic-click-activation-steps">run synthetic click activation
  steps</dfn> on an element, the user agent must <a href="#run-pre-click-activation-steps">run pre-click
  activation steps</a> on the element, then <a href="webappapis.html#fire-a-click-event">fire a <code title="event-click">click</code> event</a> at the element. The
  default action of this <code title="event-click"><a href="infrastructure.html#event-click">click</a></code> event
  must be to <a href="#run-post-click-activation-steps">run post-click activation steps</a> on the
  element. If the event is canceled, the user agent must <a href="#run-canceled-activation-steps">run
  canceled activation steps</a> on the element instead.</p>

  <p>When a pointing device is clicked, the user agent must run these
  steps:</p>

  <ol><li><p>Let <var title="">e</var> be the <a href="#nearest-activatable-element">nearest activatable
   element</a> of the element designated by the user (defined
   below), if any.</p></li>

   <li><p>If there is an element <var title="">e</var>, <a href="#run-pre-click-activation-steps">run
   pre-click activation steps</a> on it.</p></li>

   <li>

    <p>Dispatch the required <code title="event-click"><a href="infrastructure.html#event-click">click</a></code>
    event.</p> 

    <p>If there is an element <var title="">e</var>, then the default
    action of the <code title="event-click"><a href="infrastructure.html#event-click">click</a></code> event must be
    to <a href="#run-post-click-activation-steps">run post-click activation steps</a> on element <var title="">e</var>.</p>

    <p>If there is an element <var title="">e</var> but the event is
    canceled, the user agent must <a href="#run-canceled-activation-steps">run canceled activation
    steps</a> on element <var title="">e</var>.</p>

   </li>

  </ol><p class="note">The above doesn't happen for arbitrary synthetic
  events dispatched by author script. However, the <code title="dom-click"><a href="editing.html#dom-click">click()</a></code> method can be used to make it
  happen programmatically.</p>

  <p>Given an element <var title="">target</var>, the <dfn id="nearest-activatable-element">nearest
  activatable element</dfn> is the element returned by the following
  algorithm:</p>

  <ol><li><p>If <var title="">target</var> has a defined <a href="#activation-behavior">activation
   behavior</a>, then return <var title="">target</var> and abort
   these steps.</p></li>

   <li><p>If <var title="">target</var> has a parent element, then set
   <var title="">target</var> to that parent element and return to the
   first step.</p></li>

   <li><p>Otherwise, there is no <a href="#nearest-activatable-element">nearest activatable
   element</a>.</p></li>

  </ol><p>When a user agent is to <dfn id="run-pre-click-activation-steps">run pre-click activation steps</dfn>
  on an element, it must run the <dfn id="pre-click-activation-steps">pre-click activation steps</dfn>
  defined for that element, if any.</p>

  <p>When a user agent is to <dfn id="run-canceled-activation-steps">run canceled activation steps</dfn>
  on an element, it must run the <dfn id="canceled-activation-steps">canceled activation steps</dfn>
  defined for that element, if any.</p>

  <p>When a user agent is to <dfn id="run-post-click-activation-steps">run post-click activation
  steps</dfn> on an element, it must run the <dfn id="activation-behavior">activation
  behavior</dfn> defined for that element. Activation behaviors can
  refer to the <code title="event-click"><a href="infrastructure.html#event-click">click</a></code> event that was
  fired by the steps above leading up to this point.</p>

  </div><h5 id="transparent-content-models"><span class="secno">3.2.5.2 </span>Transparent content models</h5><p>Some elements are described as <dfn id="transparent">transparent</dfn>; they have
  "transparent" in the description of their content model. The content
  model of a <a href="#transparent">transparent</a> element is derived from the
  content model of its parent element: the elements required in the
  part of the content model that is "transparent" are the same
  elements as required in the part of the content model of the parent
  of the transparent element in which the transparent element finds
  itself.</p><div class="example">

   <p>For instance, an <code><a href="edits.html#the-ins-element">ins</a></code> element inside a
   <code><a href="text-level-semantics.html#the-ruby-element">ruby</a></code> element cannot contain an <code><a href="text-level-semantics.html#the-rt-element">rt</a></code>
   element, because the part of the <code><a href="text-level-semantics.html#the-ruby-element">ruby</a></code> element's
   content model that allows <code><a href="edits.html#the-ins-element">ins</a></code> elements is the part
   that allows <a href="#phrasing-content">phrasing content</a>, and the <code><a href="text-level-semantics.html#the-rt-element">rt</a></code>
   element is not <a href="#phrasing-content">phrasing content</a>.</p>

  </div><p class="note">In some cases, where transparent elements are nested
  in each other, the process has to be applied iteratively.</p><div class="example">

   <p>Consider the following markup fragment:</p>

   <pre>&lt;p&gt;&lt;object&gt;&lt;param&gt;&lt;ins&gt;&lt;map&gt;&lt;a href="/"&gt;Apples&lt;/a&gt;&lt;/map&gt;&lt;/ins&gt;&lt;/object&gt;&lt;/p&gt;</pre>

   <p>To check whether "Apples" is allowed inside the <code><a href="text-level-semantics.html#the-a-element">a</a></code>
   element, the content models are examined. The <code><a href="text-level-semantics.html#the-a-element">a</a></code>
   element's content model is transparent, as is the <code><a href="the-map-element.html#the-map-element">map</a></code>
   element's, as is the <code><a href="edits.html#the-ins-element">ins</a></code> element's, as is the part of
   the <code><a href="the-iframe-element.html#the-object-element">object</a></code> element's in which the <code><a href="edits.html#the-ins-element">ins</a></code>
   element is found. The <code><a href="the-iframe-element.html#the-object-element">object</a></code> element is found in the
   <code><a href="grouping-content.html#the-p-element">p</a></code> element, whose content model is <a href="#phrasing-content">phrasing
   content</a>. Thus, "Apples" is allowed, as text is phrasing
   content.</p>

  </div><p>When a transparent element has no parent, then the part of its
  content model that is "transparent" must instead be treated as
  accepting any <a href="#flow-content">flow content</a>.</p><h5 id="paragraphs"><span class="secno">3.2.5.3 </span>Paragraphs</h5><p class="note">The term <a href="#paragraph">paragraph</a> as defined in this
  section is distinct from (though related to) the <code><a href="grouping-content.html#the-p-element">p</a></code>
  element defined later. The <a href="#paragraph">paragraph</a> concept defined
  here is used to describe how to interpret documents.</p><p>A <dfn id="paragraph">paragraph</dfn> is typically a run of <a href="#phrasing-content">phrasing
  content</a> that forms a block of text with one or more sentences
  that discuss a particular topic, as in typography, but can also be
  used for more general thematic grouping. For instance, an address is
  also a paragraph, as is a part of a form, a byline, or a stanza in a
  poem.</p><div class="example">

   <p>In the following example, there are two paragraphs in a
   section. There is also a heading, which contains phrasing content
   that is not a paragraph. Note how the comments and
   <a href="#inter-element-whitespace">inter-element whitespace</a> do not form paragraphs.</p>

   <pre>&lt;section&gt;
  &lt;h1&gt;Example of paragraphs&lt;/h1&gt;
  This is the &lt;em&gt;first&lt;/em&gt; paragraph in this example.
  &lt;p&gt;This is the second.&lt;/p&gt;
  &lt;!-- This is not a paragraph. --&gt;
&lt;/section&gt;</pre>

  </div><p>Paragraphs in <a href="#flow-content">flow content</a> are defined relative to
  what the document looks like without the <code><a href="text-level-semantics.html#the-a-element">a</a></code>,
  <code><a href="edits.html#the-ins-element">ins</a></code>, <code><a href="edits.html#the-del-element">del</a></code>, and <code><a href="the-map-element.html#the-map-element">map</a></code> elements
  complicating matters, since those elements, with their hybrid
  content models, can straddle paragraph boundaries, as shown in the
  first two examples below.</p><p class="note">Generally, having elements straddle paragraph
  boundaries is best avoided. Maintaining such markup can be
  difficult.</p><div class="example">

   <p>The following example takes the markup from the earlier example
   and puts <code><a href="edits.html#the-ins-element">ins</a></code> and <code><a href="edits.html#the-del-element">del</a></code> elements around some
   of the markup to show that the text was changed (though in this
   case, the changes admittedly don't make much sense). Notice how
   this example has exactly the same paragraphs as the previous one,
   despite the <code><a href="edits.html#the-ins-element">ins</a></code> and <code><a href="edits.html#the-del-element">del</a></code> elements &#8212;
   the <code><a href="edits.html#the-ins-element">ins</a></code> element straddles the heading and the first
   paragraph, and the <code><a href="edits.html#the-del-element">del</a></code> element straddles the boundary
   between the two paragraphs.</p>

   <pre>&lt;section&gt;
  &lt;ins&gt;&lt;h1&gt;Example of paragraphs&lt;/h1&gt;
  This is the &lt;em&gt;first&lt;/em&gt; paragraph in&lt;/ins&gt; this example&lt;del&gt;.
  &lt;p&gt;This is the second.&lt;/p&gt;&lt;/del&gt;
  &lt;!-- This is not a paragraph. --&gt;
&lt;/section&gt;</pre>

  </div><div class="impl">

  <p>Let <var title="">view</var> be a view of the DOM that replaces
  all <code><a href="text-level-semantics.html#the-a-element">a</a></code>, <code><a href="edits.html#the-ins-element">ins</a></code>, <code><a href="edits.html#the-del-element">del</a></code>, and
  <code><a href="the-map-element.html#the-map-element">map</a></code> elements in the document with their contents. Then,
  in <var title="">view</var>, for each run of sibling <a href="#phrasing-content">phrasing
  content</a> nodes uninterrupted by other types of content, in an
  element that accepts content other than <a href="#phrasing-content">phrasing
  content</a> as well as <a href="#phrasing-content">phrasing content</a>, let <var title="">first</var> be the first node of the run, and let <var title="">last</var> be the last node of the run. For each such run
  that consists of at least one node that is neither <a href="#embedded-content">embedded
  content</a> nor <a href="#inter-element-whitespace">inter-element whitespace</a>, a
  paragraph exists in the original DOM from immediately before <var title="">first</var> to immediately after <var title="">last</var>. (Paragraphs can thus span across
  <code><a href="text-level-semantics.html#the-a-element">a</a></code>, <code><a href="edits.html#the-ins-element">ins</a></code>, <code><a href="edits.html#the-del-element">del</a></code>, and
  <code><a href="the-map-element.html#the-map-element">map</a></code> elements.)</p>

  <p>Conformance checkers may warn authors of cases where they have
  paragraphs that overlap each other (this can happen with
  <code><a href="the-iframe-element.html#the-object-element">object</a></code>, <code><a href="the-iframe-element.html#the-video-element">video</a></code>, <code><a href="the-iframe-element.html#the-audio-element">audio</a></code>, and
  <code><a href="the-canvas-element.html#the-canvas-element">canvas</a></code> elements, and indirectly through elements in
  other namespaces that allow HTML to be further embedded therein,
  like <code><a href="the-map-element.html#svg">svg</a></code> or <code><a href="the-map-element.html#math">math</a></code>).</p> 
  </div><p>A <a href="#paragraph">paragraph</a> is also formed explicitly by
  <code><a href="grouping-content.html#the-p-element">p</a></code> elements.</p><p class="note">The <code><a href="grouping-content.html#the-p-element">p</a></code> element can be used to wrap
  individual paragraphs when there would otherwise not be any content
  other than phrasing content to separate the paragraphs from each
  other.</p><div class="example">

   <p>In the following example, the link spans half of the first
   paragraph, all of the heading separating the two paragraphs, and
   half of the second paragraph. It straddles the paragraphs and the
   heading.</p>

   <pre>&lt;aside&gt;
 Welcome!
 &lt;a href="about.html"&gt;
  This is home of...
  &lt;h1&gt;The Falcons!&lt;/h1&gt;
  The Lockheed Martin multirole jet fighter aircraft!
 &lt;/a&gt;
 This page discusses the F-16 Fighting Falcon's innermost secrets.
&lt;/aside&gt;</pre>

   <p>Here is another way of marking this up, this time showing the
   paragraphs explicitly, and splitting the one link element into
   three:</p>

   <pre>&lt;aside&gt;
 &lt;p&gt;Welcome! &lt;a href="about.html"&gt;This is home of...&lt;/a&gt;&lt;/p&gt;
 &lt;h1&gt;&lt;a href="about.html"&gt;The Falcons!&lt;/a&gt;&lt;/h1&gt;
 &lt;p&gt;&lt;a href="about.html"&gt;The Lockheed Martin multirole jet
 fighter aircraft!&lt;/a&gt; This page discusses the F-16 Fighting
 Falcon's innermost secrets.&lt;/p&gt;
&lt;/aside&gt;</pre>

  </div><div class="example">

   
   <p>It is possible for paragraphs to overlap when using certain
   elements that define fallback content. For example, in the
   following section:</p>

   <pre>&lt;section&gt;
 &lt;h1&gt;My Cats&lt;/h1&gt;
 You can play with my cat simulator.
 &lt;object data="cats.sim"&gt;
  To see the cat simulator, use one of the following links:
  &lt;ul&gt;
   &lt;li&gt;&lt;a href="cats.sim"&gt;Download simulator file&lt;/a&gt;
   &lt;li&gt;&lt;a href="http://sims.example.com/watch?v=LYds5xY4INU"&gt;Use online simulator&lt;/a&gt;
  &lt;/ul&gt;
  Alternatively, upgrade to the Mellblom Browser.
 &lt;/object&gt;
 I'm quite proud of it.
&lt;/section&gt;</pre>

   <p>There are five paragraphs:</p>

   <ol class="brief"><li>The paragraph that says "You can play with my cat
    simulator. <i title="">object</i> I'm quite proud of it.", where
    <i title="">object</i> is the <code><a href="the-iframe-element.html#the-object-element">object</a></code> element.</li>

    <li>The paragraph that says "To see the cat simulator, use one of
    the following links:".</li>

    <li>The paragraph that says "Download simulator file".</li>

    <li>The paragraph that says "Use online simulator".</li>

    <li>The paragraph that says "Alternatively, upgrade to the Mellblom Browser.".</li>

   </ol><p>The first paragraph is overlapped by the other four. A user
   agent that supports the "cats.sim" resource will only show the
   first one, but a user agent that shows the fallback will
   confusingly show the first sentence of the first paragraph as
   if it was in the same paragraph as the second one, and will show
   the last paragraph as if it was at the start of the second sentence
   of the first paragraph.</p>

   <p>To avoid this confusion, explicit <code><a href="grouping-content.html#the-p-element">p</a></code> elements can be
   used.</p>

  </div><h4 id="requirements-relating-to-bidirectional-algorithm-formatting-characters"><span class="secno">3.2.6 </span>Requirements relating to bidirectional-algorithm formatting
  characters</h4><p><a href="#text-content">Text content</a> in <a href="infrastructure.html#html-elements">HTML elements</a> with
  child <a href="infrastructure.html#text-node" title="text node">text nodes</a>, and text in
  attributes of <a href="infrastructure.html#html-elements">HTML elements</a> that allow free-form text,
  may contain characters in the range U+202A to U+202E (the
  bidirectional-algorithm formatting characters). However, the use of
  these characters is restricted so that any embedding or overrides
  generated by these characters do not start and end with different
  parent elements, and so that all such embeddings and overrides are
  explicitly terminated by a U+202C POP DIRECTIONAL FORMATTING
  character. This helps reduce incidences of text being reused in a
  manner that has unforeseen effects on the bidirectional
  algorithm.</p><p>The aforementioned restrictions are defined by specifying that
  certain parts of documents form <a href="#bidirectional-algorithm-formatting-character-ranges">bidirectional-algorithm
  formatting character ranges</a>, and then imposing a requirement
  on such ranges.</p><p>The string resulting from the concatenation of the data of all of
  an <a href="infrastructure.html#html-elements" title="HTML elements">HTML element</a>'s <a href="infrastructure.html#text-node" title="text node">text nodes</a>, if any, is a <a href="#bidirectional-algorithm-formatting-character-ranges" title="bidirectional-algorithm formatting character
  ranges">bidirectional-algorithm formatting character
  range</a>.</p><p>The value of a namespace-less attribute of an <a href="infrastructure.html#html-elements" title="HTML
  elements">HTML element</a> is a <a href="#bidirectional-algorithm-formatting-character-ranges" title="bidirectional-algorithm formatting character
  ranges">bidirectional-algorithm formatting character
  range</a>.</p><p>Any strings that, as described above, are
  <dfn id="bidirectional-algorithm-formatting-character-ranges">bidirectional-algorithm formatting character ranges</dfn> must
  match the <code title="">string</code> production in the following
  ABNF, the character set for which is Unicode. <a href="references.html#refsABNF">[ABNF]</a></p><pre>string        = *( plaintext ( embedding / override ) ) plaintext
embedding     = ( lre / rle ) string pdf
override      = ( lro / rlo ) string pdf
lre           = %x202A ; U+202A LEFT-TO-RIGHT EMBEDDING
rle           = %x202B ; U+202B RIGHT-TO-LEFT EMBEDDING
lro           = %x202D ; U+202D LEFT-TO-RIGHT OVERRIDE
rlo           = %x202E ; U+202E RIGHT-TO-LEFT OVERRIDE
pdf           = %x202C ; U+202C POP DIRECTIONAL FORMATTING
plaintext     = *( %x0000-2029 / %x202F-10FFFF )
                ; any string with no bidirectional-algorithm formatting characters</pre><p class="note">For convenience, where possible authors will likely
  prefer to use the <code title="attr-dir"><a href="elements.html#the-dir-attribute">dir</a></code> attribute, the
  <code><a href="text-level-semantics.html#the-bdo-element">bdo</a></code> element, and the <code><a href="text-level-semantics.html#the-bdi-element">bdi</a></code> element, rather
  than maintaining the bidirectional-algorithm formatting characters
  manually.</p><h4 id="wai-aria"><span class="secno">3.2.7 </span><dfn>WAI-ARIA</dfn></h4><p>Authors may use the ARIA <code title="attr-aria-role">role</code>
  and <code title="attr-aria-*">aria-*</code> attributes on <a href="infrastructure.html#html-elements">HTML
  elements</a>, in accordance with the requirements described in
  the ARIA specifications, except where these conflict with the
  <span>strong native semantics</span>
  described below. These exceptions are intended to prevent authors
  from making assistive technology products report nonsensical states
  that do not represent the actual state of the document. <a href="references.html#refsARIA">[ARIA]</a></p><div class="impl">

  <p>User agents are required to implement ARIA semantics on all
  <a href="infrastructure.html#html-elements">HTML elements</a>, as defined in the ARIA
  specifications. The <span>implicit ARIA semantics</span> defined
  below must be recognized by implementations. <a href="references.html#refsARIAIMPL">[ARIAIMPL]</a></p>

  </div><p>The following table defines the <span>strong native
  semantics</span> and corresponding <span>default implicit ARIA
  semantics</span> that apply to <a href="infrastructure.html#html-elements">HTML elements</a>. Each
  language feature (element or attribute) in a cell in the first
  column implies the ARIA semantics (role, states, and/or properties)
  given in the cell in the second column of the same row. <span class="impl">When multiple rows apply to an element, the role from
  the last row to define a role must be applied, and the states and
  properties from all the rows must be combined.</span></p><table id="table-aria-strong"><thead><tr><th>Language feature
     </th><th><span>Strong native semantics</span> and <span>default implied ARIA semantics</span>

   </th></tr></thead><tbody><tr><td><code><a href="the-map-element.html#the-area-element">area</a></code> element that creates a <a href="links.html#hyperlink">hyperlink</a>
     </td><td><code title="attr-aria-role-link">link</code> role
     

    </td></tr><tr><td><code><a href="semantics.html#the-base-element">base</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-datalist-element">datalist</a></code> element
     </td><td><code title="attr-aria-role-listbox">listbox</code> role, with the <code title="attr-aria-multiselectable">aria-multiselectable</code> property set to "false"

    </td></tr><tr><td><code><a href="interactive-elements.html#the-details-element">details</a></code> element
     </td><td><code title="attr-aria-expanded">aria-expanded</code> state set to "true" if the element's <code title="attr-details-open"><a href="interactive-elements.html#attr-details-open">open</a></code> attribute is present, and set to "false" otherwise


    </td></tr><tr><td><code><a href="semantics.html#the-head-element">head</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="sections.html#the-hgroup-element">hgroup</a></code> element
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>

    </td></tr><tr><td><code><a href="grouping-content.html#the-hr-element">hr</a></code> element
     </td><td><code title="attr-aria-role-separator">separator</code> role

    </td></tr><tr><td><code><a href="semantics.html#the-html-element">html</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="embedded-content-1.html#the-img-element">img</a></code> element whose <code title="attr-img-alt"><a href="embedded-content-1.html#attr-img-alt">alt</a></code> attribute's value is empty
     </td><td><code title="attr-aria-role-presentation">presentation</code> role

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#checkbox-state" title="attr-input-type-checkbox">Checkbox</a> state
     </td><td><code title="attr-aria-checked">aria-checked</code> state set to "mixed" if the element's <code title="dom-input-indeterminate"><a href="the-input-element.html#dom-input-indeterminate">indeterminate</a></code> IDL attribute is true, or "true" if the element's <a href="association-of-controls-and-forms.html#concept-fe-checked" title="concept-fe-checked">checkedness</a> is true, or "false" otherwise

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#color-state" title="attr-input-type-color">Color</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#date-state" title="attr-input-type-date">Date</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#date-and-time-state" title="attr-input-type-datetime">Date and Time</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#local-date-and-time-state" title="attr-input-type-datetime-local">Local Date and Time</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#e-mail-state" title="attr-input-type-email">E-mail</a> state with no <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#file-upload-state" title="attr-input-type-file">File Upload</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#hidden-state" title="attr-input-type-hidden">Hidden</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#month-state" title="attr-input-type-month">Month</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#number-state" title="attr-input-type-number">Number</a> state
     </td><td><code title="attr-aria-role-spinbutton">spinbutton</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute, the <code title="attr-aria-valuemax">aria-valuemax</code> property set to the element's <a href="common-input-element-attributes.html#concept-input-max" title="concept-input-max">maximum</a>, the <code title="attr-aria-valuemin">aria-valuemin</code> property set to the element's <a href="common-input-element-attributes.html#concept-input-min" title="concept-input-min">minimum</a>, and, if the result of applying the <a href="common-microsyntaxes.html#rules-for-parsing-floating-point-number-values">rules for parsing floating point number values</a> to the element's <a href="association-of-controls-and-forms.html#concept-fe-value" title="concept-fe-value">value</a> is a number, with the <code title="attr-aria-valuenow">aria-valuenow</code> property set to that number

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#password-state" title="attr-input-type-password">Password</a> state
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#radio-button-state" title="attr-input-type-radio">Radio Button</a> state
     </td><td><code title="attr-aria-checked">aria-checked</code> state set to "true" if the element's <a href="association-of-controls-and-forms.html#concept-fe-checked" title="concept-fe-checked">checkedness</a> is true, or "false" otherwise

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#range-state" title="attr-input-type-range">Range</a> state
     </td><td><code title="attr-aria-role-slider">slider</code> role, with the <code title="attr-aria-valuemax">aria-valuemax</code> property set to the element's <a href="common-input-element-attributes.html#concept-input-max" title="concept-input-max">maximum</a>, the <code title="attr-aria-valuemin">aria-valuemin</code> property set to the element's <a href="common-input-element-attributes.html#concept-input-min" title="concept-input-min">minimum</a>, and the <code title="attr-aria-valuenow">aria-valuenow</code> property set to the result of applying the <a href="common-microsyntaxes.html#rules-for-parsing-floating-point-number-values">rules for parsing floating point number values</a> to the element's <a href="association-of-controls-and-forms.html#concept-fe-value" title="concept-fe-value">value</a>, if that results in a number, or the <a href="number-state.html#concept-input-value-default-range" title="concept-input-value-default-range">default value</a> otherwise

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#reset-button-state" title="attr-input-type-reset">Reset Button</a> state
     </td><td><code title="attr-aria-role-button">button</code> role

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#text-state-and-search-state" title="attr-input-type-search">Search</a> state with no <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#submit-button-state" title="attr-input-type-submit">Submit Button</a> state
     </td><td><code title="attr-aria-role-button">button</code> role

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#telephone-state" title="attr-input-type-tel">Telephone</a> state with no <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#text-state-and-search-state" title="attr-input-type-text">Text</a> state with no <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#text-state-and-search-state" title="attr-input-type-text">Text</a>, <a href="states-of-the-type-attribute.html#text-state-and-search-state" title="attr-input-type-search">Search</a>, <a href="states-of-the-type-attribute.html#telephone-state" title="attr-input-type-tel">Telephone</a>, <a href="states-of-the-type-attribute.html#url-state" title="attr-input-type-url">URL</a>, or <a href="states-of-the-type-attribute.html#e-mail-state" title="attr-input-type-email">E-mail</a> states with a <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-combobox">combobox</code> role, with the <code title="attr-aria-owns">aria-owns</code> property set to the same value as the <code title="attr-input-list"><a href="common-input-element-attributes.html#attr-input-list">list</a></code> attribute, and the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#time-state" title="attr-input-type-time">Time</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#url-state" title="attr-input-type-url">URL</a> state with no <a href="common-input-element-attributes.html#concept-input-list" title="concept-input-list">suggestions source element</a>
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="states-of-the-type-attribute.html#week-state" title="attr-input-type-week">Week</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>, with the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-input-readonly"><a href="common-input-element-attributes.html#attr-input-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element that is <a href="common-input-element-attributes.html#concept-input-required" title="concept-input-required">required</a>
     </td><td>The <code title="title-aria-required">aria-required</code> state set to "true"

    </td></tr><tr><td><code><a href="the-button-element.html#the-keygen-element">keygen</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="forms.html#the-label-element">label</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="semantics.html#the-link-element">link</a></code> element that creates a <a href="links.html#hyperlink">hyperlink</a>
     </td><td><code title="attr-aria-role-link">link</code> role

    </td></tr><tr><td><code><a href="interactive-elements.html#the-menu-element">menu</a></code> element with a <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#context-menu-state" title="context menu state">context menu</a> state
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="interactive-elements.html#the-menu-element">menu</a></code> element with a <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#list-state" title="list state">list</a> state
     </td><td><code title="attr-aria-role-menu">menu</code> role

    </td></tr><tr><td><code><a href="interactive-elements.html#the-menu-element">menu</a></code> element with a <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#toolbar-state" title="toolbar state">toolbar</a> state
     </td><td><code title="attr-aria-role-toolbar">toolbar</code> role

    </td></tr><tr><td><code><a href="semantics.html#the-meta-element">meta</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-meter-element">meter</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="sections.html#the-nav-element">nav</a></code> element
     </td><td><code title="attr-aria-role-navigation">navigation</code> role

    </td></tr><tr><td><code><a href="scripting-1.html#the-noscript-element">noscript</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-optgroup-element">optgroup</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-option-element">option</a></code> element that is in a <a href="the-button-element.html#concept-select-option-list" title="concept-select-option-list">list of options</a> or that represents a suggestion in a <code><a href="the-button-element.html#the-datalist-element">datalist</a></code> element
     </td><td><code title="attr-aria-role-option">option</code> role, with the <code title="attr-aria-selected">aria-selected</code> state set to "true" if the element's <a href="the-button-element.html#concept-option-selectedness" title="concept-option-selectedness">selectedness</a> is true, or "false" otherwise.

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-param-element">param</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-progress-element">progress</a></code> element
     </td><td><code title="attr-aria-role-progressbar">progressbar</code> role, with, if the progress bar is determinate, the <code title="attr-aria-valuemax">aria-valuemax</code> property set to the maximum value of the progress bar, the <code title="attr-aria-valuemin">aria-valuemin</code> property set to zero, and the <code title="attr-aria-valuenow">aria-valuenow</code> property set to the current value of the progress bar

    </td></tr><tr><td><code><a href="scripting-1.html#the-script-element">script</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-select-element">select</a></code> element with a <code title="attr-select-multiple"><a href="the-button-element.html#attr-select-multiple">multiple</a></code> attribute
     </td><td><code title="attr-aria-role-listbox">listbox</code> role, with the <code title="attr-aria-multiselectable">aria-multiselectable</code> property set to "true"

    </td></tr><tr><td><code><a href="the-button-element.html#the-select-element">select</a></code> element with no <code title="attr-select-multiple"><a href="the-button-element.html#attr-select-multiple">multiple</a></code> attribute
     </td><td><code title="attr-aria-role-listbox">listbox</code> role, with the <code title="attr-aria-multiselectable">aria-multiselectable</code> property set to "false"

    </td></tr><tr><td><code><a href="the-button-element.html#the-select-element">select</a></code> element with a <code title="attr-select-required"><a href="the-button-element.html#attr-select-required">required</a></code> attribute
     </td><td>The <code title="title-aria-required">aria-required</code> state set to "true"

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-source-element">source</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="semantics.html#the-style-element">style</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="interactive-elements.html#the-summary-element">summary</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td><code><a href="the-button-element.html#the-textarea-element">textarea</a></code> element
     </td><td><code title="attr-aria-role-textbox">textbox</code> role, with the <code title="attr-aria-multiline">aria-multiline</code> property set to "true", and the <code title="title-aria-readonly">aria-readonly</code> state set to "true" if the element has a <code title="attr-textarea-readonly"><a href="the-button-element.html#attr-textarea-readonly">readonly</a></code> attribute

    </td></tr><tr><td><code><a href="the-button-element.html#the-textarea-element">textarea</a></code> element with a <code title="attr-textarea-required"><a href="the-button-element.html#attr-textarea-required">required</a></code> attribute
     </td><td>The <code title="title-aria-required">aria-required</code> state set to "true"

    </td></tr><tr><td><code><a href="semantics.html#the-title-element">title</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>

    </td></tr><tr><td>An element that <a href="commands.html#concept-command" title="concept-command">defines a command</a>, whose <a href="commands.html#command-facet-type" title="command-facet-type">Type</a> facet is "checkbox", and that is a descendant of a <code><a href="interactive-elements.html#the-menu-element">menu</a></code> element whose <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#list-state" title="list state">list</a> state
     </td><td><code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code> role, with the <code title="attr-aria-checked">aria-checked</code> state set to "true" if the command's <a href="commands.html#command-facet-checkedstate" title="command-facet-checkedstate">Checked State</a> facet is true, and "false" otherwise

    </td></tr><tr><td>An element that <a href="commands.html#concept-command" title="concept-command">defines a command</a>, whose <a href="commands.html#command-facet-type" title="command-facet-type">Type</a> facet is "command", and that is a descendant of a <code><a href="interactive-elements.html#the-menu-element">menu</a></code> element whose <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#list-state" title="list state">list</a> state
     </td><td><code title="attr-aria-role-menuitem">menuitem</code> role

    </td></tr><tr><td>An element that <a href="commands.html#concept-command" title="concept-command">defines a command</a>, whose <a href="commands.html#command-facet-type" title="command-facet-type">Type</a> facet is "radio", and that is a descendant of a <code><a href="interactive-elements.html#the-menu-element">menu</a></code> element whose <code title="attr-menu-type"><a href="interactive-elements.html#attr-menu-type">type</a></code> attribute in the <a href="interactive-elements.html#list-state" title="list state">list</a> state
     </td><td><code title="attr-aria-role-menuitemradio">menuitemradio</code> role, with the <code title="attr-aria-checked">aria-checked</code> state set to "true" if the command's <a href="commands.html#command-facet-checkedstate" title="command-facet-checkedstate">Checked State</a> facet is true, and "false" otherwise

    </td></tr><tr><td>Element that is <a href="association-of-controls-and-forms.html#concept-fe-disabled" title="concept-fe-disabled">disabled</a>
     </td><td>The <code title="title-aria-disabled">aria-disabled</code> state set to "true"

    </td></tr><tr><td>Element with a <code title="attr-hidden"><a href="editing.html#the-hidden-attribute">hidden</a></code> attribute
     </td><td>The <code title="title-aria-hidden">aria-hidden</code> state set to "true"

    </td></tr><tr><td>Element that is a <a href="association-of-controls-and-forms.html#candidate-for-constraint-validation">candidate for constraint validation</a> but that does not <a href="association-of-controls-and-forms.html#concept-fv-valid" title="concept-fv-valid">satisfy its constraints</a>
     </td><td>The <code title="title-aria-invalid">aria-invalid</code> state set to "true"

  </td></tr></tbody></table><p>Some <a href="infrastructure.html#html-elements">HTML elements</a> have native semantics that can be
  overridden. The following table lists these elements and their
  <span>default implicit ARIA semantics</span>, along with the
  restrictions that apply to those elements. Each language feature
  (element or attribute) in a cell in the first column implies, unless
  otherwise overridden, the ARIA semantic (role, state, or property)
  given in the cell in the second column of the same row, but this
  semantic may be overridden under the conditions listed in the cell
  in the third column of that row. In addition, any element may be
  given the <code title="attr-aria-role-presentation">presentation</code> role,
  regardless of the restrictions below.</p><table id="table-aria-weak"><thead><tr><th>Language feature
     </th><th>Default implied ARIA semantic
     </th><th>Restrictions

   </th></tr></thead><tbody><tr><td><code><a href="text-level-semantics.html#the-a-element">a</a></code> element that creates a <a href="links.html#hyperlink">hyperlink</a>
     </td><td><code title="attr-aria-role-link">link</code> role
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-button">button</code>, <code title="attr-aria-role-checkbox">checkbox</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-address-element">address</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be <code title="attr-aria-role-contentinfo">contentinfo</code>

    </td></tr><tr><td><code><a href="sections.html#the-article-element">article</a></code> element
     </td><td><code title="attr-aria-role-article">article</code> role
     </td><td>Role must be either <code title="attr-aria-role-article">article</code>, <code title="attr-aria-role-document">document</code>, <code title="attr-aria-role-application">application</code>, or <code title="attr-aria-role-main">main</code>

    </td></tr><tr><td><code><a href="sections.html#the-aside-element">aside</a></code> element
     </td><td><code title="attr-aria-role-note">note</code> role
     </td><td>Role must be either <code title="attr-aria-role-note">note</code>, <code title="attr-aria-role-complementary">complementary</code>, or <code title="attr-aria-role-search">search</code>

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-audio-element">audio</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be <code title="attr-aria-role-application">application</code>

    </td></tr><tr><td><code><a href="the-button-element.html#the-button-element">button</a></code> element
     </td><td><code title="attr-aria-role-button">button</code> role
     </td><td>Role must be either <code title="attr-aria-role-button">button</code>, <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-radio">radio</code>

    </td></tr><tr><td><code><a href="interactive-elements.html#the-details-element">details</a></code> element
     </td><td><code title="attr-aria-role-group">group</code> role
     </td><td>Role must be a role that supports <code title="attr-aria-expanded">aria-expanded</code>

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-embed-element">embed</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be either <code title="attr-aria-role-application">application</code>, <code title="attr-aria-role-document">document</code>, or <code title="attr-aria-role-img">img</code>

    </td></tr><tr><td><code><a href="sections.html#the-footer-element">footer</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be <code title="attr-aria-role-contentinfo">contentinfo</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h1</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h2</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h3</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h4</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h5</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-h1-h2-h3-h4-h5-and-h6-elements">h6</a></code> element that does not have an <code><a href="sections.html#the-hgroup-element">hgroup</a></code> ancestor
     </td><td><code title="attr-aria-role-heading">heading</code> role, with the <code title="attr-aria-level">aria-level</code> property set to the element's <a href="sections.html#outline-depth">outline depth</a>
     </td><td>Role must be either <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="sections.html#the-header-element">header</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be <code title="attr-aria-role-banner">banner</code>

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-iframe-element">iframe</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be either <code title="attr-aria-role-application">application</code>, <code title="attr-aria-role-document">document</code>, or <code title="attr-aria-role-img">img</code>

    </td></tr><tr><td><code><a href="embedded-content-1.html#the-img-element">img</a></code> element whose <code title="attr-img-alt"><a href="embedded-content-1.html#attr-img-alt">alt</a></code> attribute's value is absent
     </td><td><code title="attr-aria-role-img">img</code> role
     </td><td>No restrictions

    </td></tr><tr><td><code><a href="embedded-content-1.html#the-img-element">img</a></code> element whose <code title="attr-img-alt"><a href="embedded-content-1.html#attr-img-alt">alt</a></code> attribute's value is present and not empty
     </td><td><code title="attr-aria-role-img">img</code> role
     </td><td>No restrictions

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#button-state" title="attr-input-type-button">Button</a> state
     </td><td><code title="attr-aria-role-button">button</code> role
     </td><td>Role must be either <code title="attr-aria-role-button">button</code>, <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-radio">radio</code>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#checkbox-state" title="attr-input-type-checkbox">Checkbox</a> state
     </td><td><code title="attr-aria-role-checkbox">checkbox</code> role
     </td><td>Role must be either <code title="attr-aria-role-checkbox">checkbox</code> or <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#image-button-state" title="attr-input-type-image">Image Button</a> state
     </td><td><code title="attr-aria-role-button">button</code> role
     </td><td>Role must be either <code title="attr-aria-role-button">button</code>, <code title="attr-aria-role-link">link</code>, <code title="attr-aria-role-menuitem">menuitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-radio">radio</code>

    </td></tr><tr><td><code><a href="the-input-element.html#the-input-element">input</a></code> element with a <code title="attr-input-type"><a href="the-input-element.html#attr-input-type">type</a></code> attribute in the <a href="number-state.html#radio-button-state" title="attr-input-type-radio">Radio Button</a> state
     </td><td><code title="attr-aria-role-radio">radio</code> role
     </td><td>Role must be either <code title="attr-aria-role-radio">radio</code> or <code title="attr-aria-role-menuitemradio">menuitemradio</code>

    </td></tr><tr><td><code><a href="grouping-content.html#the-li-element">li</a></code> element whose parent is an <code><a href="grouping-content.html#the-ol-element">ol</a></code> or <code><a href="grouping-content.html#the-ul-element">ul</a></code> element
     </td><td><code title="attr-aria-role-listitem">listitem</code> role
     </td><td>Role must be either <code title="attr-aria-role-listitem">listitem</code>, <code title="attr-aria-role-menuitemcheckbox">menuitemcheckbox</code>, <code title="attr-aria-role-menuitemradio">menuitemradio</code>, <code title="attr-aria-role-option">option</code>, <code title="attr-aria-role-tab">tab</code>, or <code title="attr-aria-role-treeitem">treeitem</code>

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-object-element">object</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be either <code title="attr-aria-role-application">application</code>, <code title="attr-aria-role-document">document</code>, or <code title="attr-aria-role-img">img</code>

    </td></tr><tr><td><code><a href="grouping-content.html#the-ol-element">ol</a></code> element
     </td><td><code title="attr-aria-role-list">list</code> role
     </td><td>Role must be either <code title="attr-aria-role-directory">directory</code>, <code title="attr-aria-role-list">list</code>, <code title="attr-aria-role-listbox">listbox</code>, <code title="attr-aria-role-menu">menu</code>, <code title="attr-aria-role-menubar">menubar</code>, <code title="attr-aria-role-tablist">tablist</code>, <code title="attr-aria-role-toolbar ">toolbar</code>, <code title="attr-aria-role-tree">tree</code>

    </td></tr><tr><td><code><a href="the-button-element.html#the-output-element">output</a></code> element
     </td><td><code title="attr-aria-role-status">status</code> role
     </td><td>No restrictions

    </td></tr><tr><td><code><a href="sections.html#the-section-element">section</a></code> element
     </td><td><code title="attr-aria-role-region">region</code> role
     </td><td>Role must be either
      <code title="attr-aria-role-alert">alert</code>,
      <code title="attr-aria-role-alertdialog">alertdialog</code>,
      <code title="attr-aria-role-application">application</code>,
      <code title="attr-aria-role-contentinfo">contentinfo</code>,
      <code title="attr-aria-role-dialog">dialog</code>,
      <code title="attr-aria-role-document">document</code>,
      <code title="attr-aria-role-log">log</code>,
      <code title="attr-aria-role-main">main</code>,
      <code title="attr-aria-role-marquee">marquee</code>,
      <code title="attr-aria-role-region">region</code>,
      <code title="attr-aria-role-search">search</code>, or
      <code title="attr-aria-role-status">status</code>

    </td></tr><tr><td><code><a href="grouping-content.html#the-ul-element">ul</a></code> element
     </td><td><code title="attr-aria-role-list">list</code> role
     </td><td>Role must be either <code title="attr-aria-role-directory">directory</code>, <code title="attr-aria-role-list">list</code>, <code title="attr-aria-role-listbox">listbox</code>, <code title="attr-aria-role-menu">menu</code>, <code title="attr-aria-role-menubar">menubar</code>, <code title="attr-aria-role-tablist">tablist</code>, <code title="attr-aria-role-toolbar ">toolbar</code>, <code title="attr-aria-role-tree">tree</code>

    </td></tr><tr><td><code><a href="the-iframe-element.html#the-video-element">video</a></code> element
     </td><td><a href="#concept-role-none" title="concept-role-none">No role</a>
     </td><td>If specified, role must be <code title="attr-aria-role-application">application</code>

    </td></tr><tr><td><a href="dom.html#the-body-element-0">The body element</a>
     </td><td><code title="attr-aria-role-document">document</code> role
     </td><td>Role must be either <code title="attr-aria-role-document">document</code> or <code title="attr-aria-role-application">application</code>

  </td></tr></tbody></table><p>The entry "<dfn id="concept-role-none" title="concept-role-none">no role</dfn>", when
  used as a <span title="strong native semantics">strong native
  semantic</span>, means that no role other than <code title="attr-aria-role-presentation">presentation</code> can be used.
  When used as a <span title="default implied ARIA semantics">default
  implied ARIA semantic</span>, it means the user agent has no default
  mapping to ARIA roles. (However, it probably will have its own
  mappings to the accessibility layer.)</p><div class="impl">

  <p>The WAI-ARIA specification neither requires or forbids user
  agents from enhancing native presentation and interaction behaviors
  on the basis of WAI- ARIA markup. Even mainstream user agents might
  choose to expose metadata or navigational features directly or via
  user-installed extensions; for example, exposing required form
  fields or landmark navigation. User agents are encouraged to
  maximize their usefulness to users, including users without
  disabilities.</p>
<!-- EDITORIAL -->

  <p>Conformance checkers are encouraged to phrase errors such that
  authors are encouraged to use more appropriate elements rather than
  remove accessibility annotations. For example, if an <code><a href="text-level-semantics.html#the-a-element">a</a></code>
  element is marked as having the <code title="attr-aria-role-button">button</code> role, a conformance
  checker could say "Use a more appropriate element to represent a
  button, for example a <code><a href="the-button-element.html#the-button-element">button</a></code> element or an
  <code><a href="the-input-element.html#the-input-element">input</a></code> element" rather than "The <code title="attr-aria-role-button">button</code> role cannot be used with
  <code><a href="text-level-semantics.html#the-a-element">a</a></code> elements".</p>

  </div><div class="example">

   <p>These features can be used to make accessibility tools render
   content to their users in more useful ways. For example, ASCII art,
   which is really an image, appears to be text, and in the absence of
   appropriate annotations would end up being rendered by screen
   readers as a very painful reading of lots of punctuation. Using the
   features described in this section, one can instead make the ATs
   skip the ASCII art and just read the caption:</p>

   <pre>&lt;figure <strong>role="img" aria-labelledby="fish-caption"</strong>&gt; 
 &lt;pre&gt;
 o           .'`/
     '      /  (
   O    .-'` ` `'-._      .')
      _/ (o)        '.  .' /
      )       )))     &gt;&lt;  &lt;
      `\  |_\      _.'  '. \
        '-._  _ .-'       '.)
    jgs     `\__\
 &lt;/pre&gt;
 &lt;figcaption <strong>id="fish-caption"</strong>&gt;
  Joan G. Stark, "&lt;cite&gt;fish&lt;/cite&gt;".
  October 1997. ASCII on electrons. 28&#215;8.
 &lt;/figcaption&gt; 
&lt;/figure&gt; 
   </pre>

   

  </div></body></html>