Iframe

This article is about the HTML elements in general. For information on how to format World Heritage Encyclopedia entries, see Help:Wiki markup and Help:HTML in wikitext.

An HTML element is an individual component of an HTML document or "web page", once this has been parsed into the Document Object Model. HTML is composed of a tree of HTML elements and other nodes, such as text nodes. Each element can have HTML attributes specified. Elements can also have content, including other elements and text. HTML elements represent semantics, or meaning. For example, the title element represents the title of the document.

In the HTML syntax, most elements are written with a start tag and an end tag, with the content in between. An HTML tag is composed of the name of the element, surrounded by angle brackets. An end tag also has a slash after the opening angle bracket, to distinguish it from the start tag. For example, a paragraph, which is represented by the p element, would be written as

In the HTML syntax, most elements are written ...

However, not all of these elements require the end tag, or even the start tag, to be present. Some elements, the so-called void elements, do not have an end tag. A typical example is the br element, which represents a significant line break, such as in a poem or an address. A void element's behaviour is predefined, and it can not contain any content or other elements. For example, the address of the dentist in Finding Nemo would be written as

P. Sherman
42 Wallaby Way
Sydney

When using an XHTML DTD, it is required to open and close the element with a single tag. To specify that it is a void element, a "/" is included at the end of the tag (not to be confused with the "/" at the beginning of a closing tag).

P. Sherman
42 Wallaby Way
Sydney

HTML attributes are specified inside the start tag. For example, the abbr element, which represents an abbreviation, expects a title attribute within its opening tag. This would be written as

abbr.

Concepts

Document vs. DOM

HTML documents are delivered as "documents".[note 1] These are then parsed, which turns them into the Document Object Model (DOM) internal representation, within the web browser.[note 2][note 3]

Presentation by the web browser, such as screen rendering or access by JavaScript, is then performed on this internal model, not the original document.

Early HTML documents, and to a lesser extent today, were largely invalid HTML and riddled with syntax errors. The parsing process was also required to "fix-up" these errors, as best it could. The resultant model was often not correct (i.e. it did not represent what a careless coder had originally intended), but it would at least be valid, according to the HTML standard. A valid model was produced, no matter how bad the "tag soup" supplied had been. Only in the rarest cases would the parser abandon parsing altogether.

Elements vs. tags

"Elements" and "tags" are terms that are widely confused. HTML documents contain tags, but do not contain the elements. The elements are only generated after the parsing step, from these tags.

As is generally understood, the position of an element is indicated as spanning from a start tag, possibly including some child content, and is terminated by an end tag.[3] This is the case for many, but not all, elements within an HTML document.

As HTML is based on SGML,[4] its parsing also depends on the use of a DTD, specifically an HTML DTD such as that for HTML 4.01.[5][note 4] The DTD specifies which element types are possible (i.e. it defines the set of element types that go to make up HTML) and it also specifies the valid combinations in which they may appear in a document. It is part of general SGML behaviour that where only one valid structure is possible (per the DTD), it is not generally a requirement that the document explicitly states that structure. As a simple example, the

start tag indicating the start of a paragraph element should be closed by a

end tag, indicating the end of the element. Also the DTD states that paragraph elements cannot be nested. The HTML document fragment:

Para 1

Para 2

Para 3

can thus be inferred to be equivalent to:

Para 1

Para 2

Para 3

(If one paragraph element cannot contain another, any currently open paragraph must be closed before starting another.)

Because of this implied behaviour, based on the combination of the DTD and the individual document, it is not possible to infer elements from the document tags alone, but only by also using an SGML or HTML aware parser, with knowledge of the DTD.

SGML vs. XML

SGML is complex, which has limited its widespread adoption and understanding. XML was developed as a simpler alternative. XML is similar to SGML, and can also use the DTD mechanism to specify the elements supported and their permitted combinations as document structure. XML parsing is however simpler. The relation from tags to elements is always simply that of parsing the actual tags included in the document, without the implied closures that are part of SGML.[note 5]

Where HTML can be formed as XML, either through XHTML or through HTML5 as XML, the parsing from document tags to DOM elements is simplified, but still follows the same basic process. Once the DOM of elements is obtained, behaviour beyond that point (i.e. screen rendering) is identical.[note 6]

Content vs. presentation

Since HTML 4, HTML has increasingly focussed on the separation of content from presentation.[7] This is often referred to as a separation of concerns. HTML is used to represent the structure or content of a document, its presentation remains the sole responsibility of CSS. A default style sheet is suggested as part of the CSS standard, giving a default rendering for HTML.[8]

%block; vs. box

Part of this CSS presentation behaviour is the notion of the "box model". This is applied to those elements that CSS considers to be "block" elements, set through the CSS display: block; statement.

HTML also has a similar concept, although different, and the two are very frequently confused. %block; and %inline; are groups within the HTML DTD that group elements as being either "block-level" or "inline".[9] This is used to define their nesting behaviour: block-level elements cannot be placed into an inline context.[note 7] This behaviour cannot be changed, it is fixed in the DTD. Block and inline elements have the appropriate and different CSS behaviours attached to them by default,[9] including the relevance of the box model for particular element types.

Note though that this CSS behaviour can, and frequently is, changed from the default. Lists with

  • ... are %block; elements and are presented as block elements by default. However, it is quite common to set these with CSS to display as an inline list.[10]

    Overview

    Syntax


    There are multiple kinds of HTML elements: void elements, raw text elements, and normal elements.

    Void elements only have a start tag, which contains any HTML attributes. They may not contain any children, such as text or other elements. Often they are place holders for elements which reference external files, such as the image () element. The attributes included in the element will then point to the external file in question. Another example of a void element is the link element, for which the syntax is

    This link element points the browser at a style sheet to use when presenting the HTML document to the user. Note that in the HTML syntax, attributes don't have to be quoted. When using the XML syntax (XHTML), on the other hand, all attributes must be quoted, and a trailing slash is required before the last angle bracket:

    Raw text elements are constructed with:

    • a start tag () marking the beginning of an element, which may incorporate any number of HTML attributes;
    • some amount of text content, but no elements (all tags, apart from the applicable end tag, will be interpreted as content);
    • an end tag, in which the element name is prefixed with a slash: . In some versions of HTML, the end tag is optional for some elements. The end tag is required in XHTML.[examples needed]

    Normal elements usually have both a start tag and an end tag, although for some elements the end tag, or both tags, can be omitted. It is constructed in a similar way:

    • a start tag () marking the beginning of an element, which may incorporate any number of HTML attributes;
    • some amount of content, including text and other elements;
    • an end tag, in which the element name is prefixed with a slash: .

    HTML attributes define desired behaviour or indicate additional element properties. Most attributes require a value. In HTML, the value can be left unquoted if it doesn't include spaces (name=value), or it can be quoted with single or double quotes (name='value' or name="value"). In XML, those quotes are required. Boolean attributes, on the other hand, don't require a value to be specified. An example is the checked for checkboxes:

    In the XML syntax, though, the name should be repeated as the value:

    Informally, HTML elements are sometimes referred to as "tags" (an example of synecdoche), though many prefer the term tag strictly in reference to the markup delimiting the start and end of an element.

    Element (and attribute) names may be written in any combination of upper or lower case in HTML, but must be in lower case in XHTML.[11] The canonical form was upper-case until HTML 4, and was used in HTML specifications, but in recent years, lower-case has become more common.

    Element standards

    HTML elements are defined in a series of freely available open standards issued since 1995, initially by the IETF and subsequently by the W3C.

    Since the early 1990s, developers of user agents (e.g. web browsers) have often developed their own elements, some of which have been adopted in later standards. Other user agents may not recognize non-standard elements, and they may be ignored or displayed improperly.

    In 1998, XML (a simplified form of SGML) introduced mechanisms to allow anyone to develop their own elements and incorporate them in XHTML documents, for use with XML-aware user agents.[12]

    Subsequently, HTML 4.01 was rewritten in an XML-compatible form, XHTML 1.0 (eXtensible HTML). The elements in each are identical, and in most cases valid XHTML 1.0 documents will be valid or nearly valid HTML 4.01 documents. This article mainly focuses on real HTML, unless noted otherwise; however, it remains applicable to XHTML. (See HTML for a discussion of the minor differences between the two).

    Element status

    Since the first version of HTML, several elements have become outmoded, and are deprecated in later standards, or do not appear at all, in which case they are invalid (and will be found invalid, and perhaps not displayed, by validating user agents).[13]

    At present, the status of elements is complicated by the existence of three types of HTML 4.01 / XHTML 1.0 DTD:

    • Transitional, which contain deprecated elements, but which were intended to provide a transitional period during which authors could update their practices;
    • Frameset, which are versions of the Transitional DTDs which also allow authors to write frameset documents;
    • Strict, which is the up-to date (as at 1999) form of HTML.

    The first Standard (HTML 2.0) contained four deprecated elements, one of which was invalid in HTML 3.2. All four are invalid in HTML 4.01 Transitional, which also deprecated a further ten elements. All of these, plus two others, are invalid in HTML 4.01 Strict. While the frame elements are still current in the sense of being present in the Transitional and Frameset DTDs, there are no plans to preserve them in future standards, as their function has been largely replaced, and they are highly problematic for user accessibility.

    (Strictly speaking, the most recent XHTML standard, XHTML 1.1 (2001), does not include frames at all; it is approximately equivalent to XHTML 1.0 Strict, but also includes the Ruby markup module.)[14]

    A common source of confusion is the loose use of deprecated to refer to both deprecated and invalid status, and to elements which are expected to be formally deprecated in future.

    Presentation and behaviour

    In keeping with the principle of separation of concerns, the function of HTML is primarily to add structural and semantic information to the raw text of a document. Presentation and behaviour are separate functions, which can be added as desired, ideally through links to external documents such as style sheets, graphics files, and scripts.

    This allows the document to be presented by different user agents according to their purposes and abilities; for example, a user agent can select an appropriate style sheet to present a document by displaying on a monitor, printing on paper, or to determine speech characteristics in an aural user agent. The structural and semantic functions of the markup remain identical in each case.

    Historically, user agents did not always support these features. In the 1990s, as a stop-gap, presentational elements were added to HTML, at the cost of creating problems for interoperability and user accessibility. This is now regarded as outmoded and has been superseded by style sheet-based design; most presentational elements are now deprecated.[15]

    External image files are incorporated with the img or object elements. (With XHTML, the SVG language can also be used to write graphics within the document, though linking to external SVG files is generally simpler.)[16] Where an image is not purely decorative, HTML allows replacement content with similar semantic value to be provided for non-visual user agents.

    An HTML document can also be extended through the use of scripts to provide additional behaviours beyond the abilities of HTML hyperlinks and forms.

    The elements style and script, with related HTML attributes, provide reference points in HTML markup for links to style sheets and scripts. They can also contain instructions directly.

    • In the document head, script and style may either link to shared external documents, or contain embedded instructions. (The link element can also be used to link style sheets.)
    • The style attribute is valid in most document body elements for inclusion of inline style instructions.
    • Event-handling attributes, which provide links to scripts, are optional in most elements.
    • script can occur at any point in the document body.
    • For user agents which do not operate scripts, the noscript element provides alternative content where appropriate; however, it can only be used as a block-level element.

    List of all HTML elements

    element 
    Tag Description
    Defines a comment
    Defines the document type
    Defines a hyperlink
    Defines an abbreviation
    Not supported in HTML5. Defines an acronym
    Defines contact information for the author/owner of a document
    Not supported in HTML5. Deprecated in HTML 4.01. Defines an embedded applet
    Defines an area inside an image-map
    Defines an article
    Defines content aside from the page content
    Defines sound content
    Defines bold text
    Specifies the base URL/target for all relative URLs in a document
    Not supported in HTML5. Deprecated in HTML 4.01. Specifies a default colour, size, and font for all text in a document
    Isolates a part of text that might be formatted in a different direction from other text outside it
    Overrides the current text direction
    Not supported in HTML5. Defines big text
    Defines a section that is quoted from another source
    Defines the document's body

    Defines a single line break
    Used to draw graphics, on the fly, via scripting (usually JavaScript)
    Defines a table caption
    Not supported in HTML5. Deprecated in HTML 4.01. Defines centred text
    Defines the title of a work
    Defines a piece of computer code
    Specifies column properties for each column within a
    Specifies a group of one or more columns in a table for formatting
    Defines a command button that a user can invoke
    Specifies a list of pre-defined options for input controls
    Defines a description of an item in a definition list
    Defines text that has been deleted from a document
    Defines additional details that the user can view or hide
    Defines a definition term
    Defines a dialog box or window
    Not supported in HTML5. Deprecated in HTML 4.01. Defines a directory list
    Defines a section in a document
    Defines a definition list
    Defines a term (an item) in a definition list
    Defines emphasized text 
    Defines a container for an external (non-HTML) application
    Groups related elements in a form
    Defines a caption for a
    element
    Specifies self-contained content
    Not supported in HTML5. Deprecated in HTML 4.01. Defines font, colour, and size for text
    Defines a footer for a document or section
    Defines an HTML form for user input
    Not supported in HTML5. Defines a window (a frame) in a frameset
    Not supported in HTML5. Defines a set of frames

    to

    Defines HTML headings
    Defines information about the document
    Defines a header for a document or section
    Groups heading (

    to

    ) elements

    Defines a thematic change in the content
    Defines the root of an HTML document
    Defines a part of text in an alternate voice or mood
    An inline frame places another HTML document in a frame. Unlike an object element, an inline frame can be the "target" frame for links defined by other elements, and it can be selected by the user agent as the focus for printing, viewing its source, and so on.
    The content of the element is used as alternative text to be displayed if the browser does not support i-frames.
    First introduced by Microsoft Internet Explorer in 1997, standardized in HTML 4.0 Transitional, allowed in HTML 5.

    Longdesc

    In HTML, longdesc is an attribute used within the image element, frame element, or iframe element. It is supposed to be a URL[note 8] to a document that provides a long description for the image, frame, or i-frame in question.[36] Note that this attribute should contain a URL, and not as is commonly mistaken, the text of the description itself.

    Longdesc was designed to be used by screen readers to display image information for computer users with accessibility issues, such as the blind or visually impaired, and is widely implemented by both web browsers and screen readers.[37] Some developers object that [38] it is actually seldom used for this purpose, because there are relatively few authors who use the attribute, and most of those authors use it incorrectly, and have used this argument to recommend dropping longdesc.[39] The publishing industry has responded, advocating the retention of longdesc.[40]

    Example

    Content of description.html:

    ...
    

    This is an image of a two-layered birthday cake.

    ...

    Linking to the long description in the text

    Since very few Graphical browsers support making the link available natively (Opera and iCab being the exceptions), it is useful to include a link to the description page near the img element whenever possible, as this can also aid sighted users.

    Example
     [D]

    Historic elements

    Main article: Comparison of layout engines (Non-standard HTML)

    The following elements were part of the early HTML developed by Tim Berners-Lee from 1989–91; they are mentioned in HTML Tags, but deprecated in HTML 2.0 and were never part of HTML standards.

    ... (obsolete)
    </code> (obsolete) </dt> <dd> </dd> <dt><span id="xmp"></span><span id="xmp_tag"></span><code class="html htmlelement"><xmp>...</xmp></code> (obsolete) </dt> <dd>These elements were used to show fixed-width text; their use was replaced by <code>pre</code>. </dd> <dd><b><code>plaintext</code></b> <i>cannot</i> have an end tag – it terminates the markup and causes the rest of the document to be parsed as if it were <a href="/articles/Plain_text" title="Plain text">plain text</a>. </dd> <dd>These existed in <i><a href="#HTMLTAGS">HTML Tags</a></i>; <b>deprecated</b> in <a href="#HTML20">HTML 2.0</a>; <b>invalid</b> in <a href="#HTML401">HTML 4.0</a>. </dd> <dt><span id="nextid"></span><span id="nextid_tag"></span><code class="html htmlelement"><nextid>...</nextid></code> (obsolete) </dt> <dd>This element related to the original NeXT http server, and was not used once the web had spread to other systems. </dd> <dd><code>nextid</code> existed in <i><a href="#HTMLTAGS">HTML Tags</a></i> (described as obsolete); <b>deprecated</b> in <a href="#HTML20">HTML 2.0</a>; <b>invalid</b> in <a href="#HTML32">HTML 3.2</a> and later. </dd> </dl> <h2><span class="mw-headline" id="Non-standard_elements">Non-standard elements</span></h2> <div class="hatnote relarticle mainarticle">Main article: <span>Comparison of layout engines (Non-standard HTML)</span></div> <p>This section lists some widely used obsolete elements, which means they are not used in <a href="/articles/Validator" title="Validator">valid</a> code. They may not be supported in all user agents. </p> <dl> <dt><span id="blink"></span><a href="/articles/Blink_element" title="Blink element"><code class="html htmlelement"><blink>...</blink></code></a> (obsolete) </dt> <dd>Causes text to blink. Can be done with CSS where supported: <code>{text-decoration: blink}</code> (This effect may have negative consequences for people with <a href="/articles/Photosensitive_epilepsy" title="Photosensitive epilepsy">photosensitive epilepsy</a>;<sup id="cite_ref-WCAG_49-0" class="reference"><a href="#cite_note-WCAG-49"><span>[</span>41<span>]</span></a></sup> its use on the public Internet should follow the appropriate guidelines.) </dd> <dd><code>blink</code> originated in <a href="/articles/Netscape_Navigator" title="Netscape Navigator">Netscape Navigator</a> and is mostly recognized by its descendants, including <a href="/articles/Firefox" title="Firefox">Firefox</a>; <b>deprecated</b> or <b>invalid</b> in <a href="#HTML20">HTML 2.0</a> and later. Note that the replacement CSS tag, while standard, is not required to be supported. </dd> <dt><span id="marquee"></span><a href="/articles/Marquee_element" title="Marquee element"><code class="html htmlelement"><marquee>...</marquee></code></a> </dt> <dd>Creates scrolling text. Can be done with scripting instead. (This effect may have negative consequences for people with <a href="/articles/Photosensitive_epilepsy" title="Photosensitive epilepsy">photosensitive epilepsy</a>;<sup id="cite_ref-WCAG_49-1" class="reference"><a href="#cite_note-WCAG-49"><span>[</span>41<span>]</span></a></sup> its use on the public Internet should follow the appropriate guidelines.) There are three options, including <b>Alternate</b>, <b>Scroll</b> and <b>slide</b>. <b>Scrolldelay</b> can also be added. </dd> <dd><code>marquee</code> originated in <a href="/articles/Microsoft_Internet_Explorer" title="Microsoft Internet Explorer" class="mw-redirect">Microsoft Internet Explorer</a>; <b>deprecated</b> or <b>invalid</b> in <a href="#HTML20">HTML 4.01</a> and later. </dd> <dt><span id="nobr"></span><code class="html htmlelement"><nobr>...</nobr></code> </dt> <dd>Causes text to not break at end of line, preventing word wrap where text exceeds the width of the enclosing object. Adjacent text may break before and after it. Can be done with CSS: <code>{white-space: nowrap;}</code> </dd> <dd><code>nobr</code> is a proprietary element which is recognized by most browsers for compatibility reasons; <b>deprecated</b> or <b>invalid</b> in <a href="#HTML20">HTML 2.0</a> and later. </dd> <dt><span id="noembed"></span><code class="html htmlelement"><noembed>...</noembed></code> (obsolete) </dt> <dd>Specifies alternative content, if the embed cannot be rendered. Replaced by the content of the <code>embed</code> or <code>object</code> element. </dd> </dl> <h2><span class="mw-headline" id="Previously_obsolete_but_added_back_in_HTML_5">Previously obsolete but added back in HTML 5</span></h2> <dl> <dt><span id="embed"></span><code class="html htmlelement"><embed>...</embed></code> </dt> <dd>Inserts a non-standard object (like applet) or external content (typically non-HTML) into the document. Deprecated in HTML 4 in favor of the <code>object</code> tag, but then was added back into the HTML 5 specification<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span>[</span>42<span>]</span></a></sup><sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span>[</span>43<span>]</span></a></sup> </dd> </dl> <p><span id="menu"></span><span id="menu_tag"></span><b><code class="html htmlelement"><menu>...</menu></code></b> </p> <dl> <dd>HTML 2.0: A menu listing. Should be more compact than a <code><ul></code> list. </dd> <dd><code>MENU</code> existed in <i><a href="#HTMLTAGS">HTML Tags</a></i>, and was <b>standardized</b> in <a href="#HTML20">HTML 2.0</a>; <b>deprecated</b> in <a href="#HTML401">HTML 4.0 Transitional</a>; <b>invalid</b> in <a href="#HTML401">HTML 4.0 Strict</a>; but then redefined in <a href="/articles/HTML5" title="HTML5">HTML 5</a>. </dd> </dl> <h2><span class="mw-headline" id="Comments">Comments</span></h2> <dl> <dt><code><!-- A Comment --></code> </dt> <dd>A <a href="/articles/Comment_(computer_programming)" title="Comment (computer programming)">comment</a> can appear anywhere in a document, even before the doctype, but not in other tags. (However, placing comments – or indeed any characters except for white-space – before the doctype will cause Internet Explorer 6 to use <a href="/articles/Quirks_mode" title="Quirks mode">quirks mode</a> for the document.) None of its enclosed contents are processed. For compatibility with some pre-1995 browsers, the contents of <code>style</code> and <code>script</code> elements are still sometimes surrounded by comment delimiters. </dd> <dd>Comments do not nest: the markup <code><!--Xbegin<!--Y-->Xend--></code> will yield the comment <code>Xbegin<!--Y</code> and the text <code>Xend--></code> after it. </dd> </dl> <h2><span class="mw-headline" id="Notes">Notes</span></h2> <div class="reflist" style="list-style-type: lower-roman;"> <ol class="references"> </ol></div> <h2><span class="mw-headline" id="References">References</span></h2> <div class="reflist columns references-column-width" style="-moz-column-width: 35em; -webkit-column-width: 35em; column-width: 35em; list-style-type: decimal;"> <ol class="references"> </ol></div> <h2><span class="mw-headline" id="Bibliography">Bibliography</span></h2> <div class="refbegin" style=""> <h3><span class="mw-headline" id="HTML_standards">HTML standards</span></h3> <dl> <dt><span id="HTML20">HTML 2.0:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-30"><!----></span></strong> </dd> </dl> <dl> <dt><span id="HTML32">HTML 3.2:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-31"><!----></span></strong> </dd> </dl> <dl> <dt><span id="HTML401">HTML 4.01:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-32"><!----></span></strong> <i>(HTML 4.01 is the updated form of HTML 4.0.)</i> </dd> </dl> <dl> <dt><span id="XHTML10">XHTML 1.0:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-33"><!----></span></strong> </dd> </dl> <dl> <dt><span id="XHTML11">XHTML 1.1:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-34"><!----></span></strong> </dd> </dl> <h3><span class="mw-headline" id="Other_sources">Other sources</span></h3> <dl> <dt><i><span id="HTMLTAGS">HTML Tags:</span></i> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-35"><!----></span></strong> <i>(Part of the first published description of HTML.)</i> </dd> </dl> <dl> <dt><i><span id="HTMLDRAFT12">HTML Internet Draft 1.2:</span></i> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-36"><!----></span></strong> </dd> </dl> <dl> <dt><i><span id="HTML30">HTML 3.0 Drafts:</span></i> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-37"><!----></span></strong> <i>(This is the final draft of HTML 3.0, which expired without being developed further.)</i> </dd> </dl> <dl> <dt><i><span id="HTMLTABLES">HTML Tables:</span></i> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-38"><!----></span></strong> </dd> </dl> <dl> <dt><span id="XML10">XML 1.0:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-39"><!----></span></strong> </dd> </dl> <dl> <dt><span id="CSS1">CSS:</span> </dt> <dd><strong class="error"><span class="scribunto-error" id="mw-scribunto-error-40"><!----></span></strong> </dd> </dl> </dl></div> <h2><span class="mw-headline" id="External_links">External links</span></h2> <ul> <li> Complete lists of attributes for HTML 4.01 </li> </ul> <div style='width: 100%; margin-top: 25px;'> <div class='citationalSource' style='text-align: center; float: right;padding-bottom: 10px;'></div> </div> <div class='citationalSource' style='width: 100%; margin-top: 75px;'> <div style='text-align: center; float: right;'> This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. 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