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	<header>
		<title>Techniques for <abbr expansion="Web Content Accessibility Guidelines">WCAG</abbr> 2.0</title>
		<subtitle>Techniques and Failures for Web Content Accessibility Guidelines 2.0</subtitle>
		<w3c-designation>WCAG20-TECHS</w3c-designation>
		<w3c-doctype>Public Editors' Draft</w3c-doctype>
		<pubdate>
			<day>14</day>
			<month>March</month>
			<year>2013</year>
		</pubdate>
		<publoc>
			<loc href="http://www.w3.org/WAI/GL/2013/WD-WCAG20-TECHS-20130314/">http://www.w3.org/WAI/GL/2013/WD-WCAG20-TECHS-20130314/</loc>
			<!-- <loc href="http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/">http://www.w3.org/TR/2012/NOTE-WCAG20-TECHS-20120103/</loc> -->
		</publoc>
		<altlocs>
			<loc href="complete.html">Single file version</loc>
			<loc href="complete-diff.html">Single file diff-marked version showing revisions since 3 January 2012</loc>
			<loc href="/WAI/WCAG20/versions/techniques/">Alternate Versions of Techniques for WCAG 2.0</loc>
		</altlocs>
		<latestloc>
			<loc href="http://www.w3.org/TR/WCAG20-TECHS/">http://www.w3.org/TR/WCAG20-TECHS/</loc>
			<!-- <loc href="http://www.w3.org/WAI/GL/WCAG20-TECHS/">http://www.w3.org/WAI/GL/WCAG20-TECHS/</loc> -->
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		<prevlocs>
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			<loc href="http://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20120103/">http://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20120103/</loc>
		</prevlocs>
		<authlist>
			<author role="current">
				<name>Michael Cooper</name>
				<affiliation>W3C</affiliation>
			</author>
			<author role="current">
				<name>Loretta Guarino Reid</name>
				<affiliation>Google, Inc.</affiliation>
			</author>
			<author role="current">
				<name>Gregg Vanderheiden</name>
				<affiliation>Trace R&amp;D Center, University of
					Wisconsin-Madison</affiliation>
			</author>
			<author role="past">
				<name>Ben Caldwell</name>
				<affiliation>(until September 2010 while at Trace R&amp;D Center, University of
					Wisconsin-Madison)</affiliation>
			</author>
			<author role="past">
				<name>Wendy Chisholm</name>
				<affiliation>(until July 2006 while at W3C)</affiliation>
			</author>
			<author role="past">
				<name>John Slatin</name>
				<affiliation>(until June 2006 while at Accessibility Institute, University of Texas at
					Austin)</affiliation>
			</author>
		</authlist>
		<status>
			<p><emph>This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the <loc href="http://www.w3.org/TR/">W3C technical reports index</loc> at <loc href="http://www.w3.org/TR/">http://www.w3.org/TR/</loc>.</emph></p>
			<p>This is a Working Group Note <!--<phrase>Public Editors' Draft of</phrase>--> "Techniques for WCAG 2.0". These techniques are produced by the <loc href="http://www.w3.org/WAI/GL/">Web Content Accessibility Guidelines Working Group</loc> to provide guidance about how to conform to the <loc href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">Web Content Accessibility Guidelines (WCAG) 2.0 Recommendation</loc>. Techniques are referenced from <loc href="http://www.w3.org/TR/2008/NOTE-UNDERSTANDING-WCAG20-20081211/">Understanding WCAG 2.0</loc> and <loc href="http://www.w3.org/WAI/WCAG20/quickref/20081211/">How to Meet WCAG 2.0</loc>. Please note that the contents of this document are informative (they provide guidance), and not normative (they do not set requirements for conforming to WCAG 2.0).</p>
			<p>WCAG 2.0 Techniques was <loc href="http://www.w3.org/TR/WCAG20-TECHS/">previously published on 11 December 2008</loc> as a Working Group Note and updated 14 October 2010. This new version updates the support information provided for WCAG 2.0. Note that WCAG 2.0 itself remains unchanged, only the informative support materials have been updated. Primary changes include addition of PDF and Silverlight techniques, and clarifications based on input from the public and translators. <!--<phrase role="ext-review">The purpose of this draft is to collect public feedback on proposed changes since the <loc href="http://www.w3.org/TR/2010/NOTE-WCAG20-TECHS-20101014/">WCAG 2.0 Techniques Working Group Note of 14 October 2010</loc>. The Working Group intends to publish an updated Note once feedback from this review has been incorporated. <emph role="bold">The existing Techniques document remains in place as a W3C Note</emph> while this separate draft update is under review and the WCAG Working Group addresses comments. Draft updates include addition of PDF and Silverlight techniques, and clarifications based on input from the public and translators.</phrase>--> The changes are highlighted in the <loc href="complete-diff">diff-marked version</loc>.</p>
			<p><!--<phrase role="ext-review">Comments on this draft are due <emph role="bold">on or before 26 August 2011</emph>.</phrase>--> The Working Group requests that any comments be made using the provided <loc href="http://www.w3.org/WAI/WCAG20/comments/">online comment form</loc>. If this is not possible, comments can also be sent to <loc href="mailto:public-comments-wcag20@w3.org">public-comments-wcag20@w3.org</loc>. The <loc href="http://lists.w3.org/Archives/Public/public-comments-wcag20/">archives for the public comments list</loc> are publicly available. Comments received on this document may be addressed in future versions of this document, or in another manner. <!--The Working Group does not plan to make formal responses to comments. -->Archives of the <loc href="http://lists.w3.org/Archives/Public/w3c-wai-gl/">WCAG WG mailing list discussions</loc> are also publicly available, and future work undertaken by the Working Group may address comments received on this document.</p>
			<p>Materials from the public to assist in documenting techniques are particularly welcomed. Please use the <loc href="http://www.w3.org/WAI/GL/WCAG20/TECHS-SUBMIT/">Techniques Submission Form</loc> to submit techniques. </p>
			<p>This document has been produced as part of the W3C <loc href="http://www.w3.org/WAI/">Web Accessibility Initiative</loc> (WAI). The goals of the WCAG Working Group are discussed in the <loc href="http://www.w3.org/WAI/GL/new-charter-2000.html">WCAG Working Group charter</loc>. The WCAG Working Group is part of the <loc href="http://www.w3.org/WAI/Technical/Activity">WAI Technical Activity</loc>.</p>
			<p> Publication as a Working Group Note<!--<phrase role="ext-review">Public Editors' Draft</phrase>--> does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress. </p>
			<p>This document was produced by a group operating under the <loc href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent Policy</loc>. W3C maintains a <loc role="disclosures" href="http://www.w3.org/2004/01/pp-impl/35422/status">public list of any patent disclosures</loc> made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains <loc href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</loc> must disclose the information in accordance with <loc href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the W3C Patent Policy</loc>. </p>
		</status>
		<abstract>
			<p>&quot;Techniques for WCAG 2.0&quot;  provides information to Web content developers who wish to  satisfy the success criteria of <loc href="http://www.w3.org/TR/WCAG20/">Web Content Accessibility Guidelines (WCAG) 2.0</loc> <bibref ref="WCAG20"/>. Techniques are specific authoring practices that may be used in support of the WCAG 2.0 success criteria. This document provides &quot;General Techniques&quot; that describe basic practices that are applicable to any technology, and technology-specific techniques that provide information applicable to specific technologies. <phrase diff="del">The World Wide Web Consortium  only documents techniques for non-proprietary technologies; the WCAG Working Group hopes vendors of other technologies will provide similar techniques to describe how to conform to WCAG 2.0 using those technologies. </phrase><phrase diff="add">Technology-specific techniques do not supplant the general techniques: content developers should consider both general techniques and technology-specific techniques as they work toward conformance. </phrase>Use of the techniques provided in this document makes it easier for Web  content to demonstrate conformance to WCAG 2.0 success criteria than if  these techniques are not used.</p>
			<p diff="add">In addition to techniques for addressing the success criteria, "Common Failures" are also documented. These "Common Failures" are authoring practices that are known to cause Web content to fail to conform to WCAG 2.0. Authors must avoid those practices in order to meet the WCAG 2.0 Success Criteria.</p>
			<p>Besides the techniques provided in this document, there may be other techniques that  can be used to  implement conformance to WCAG 2.0. The WCAG WG encourages submission of such techniques so they can be considered for  inclusion in this document, in order to make the set of techniques maintained by the  WCAG WG as comprehensive as possible.  Please submit techniques for  consideration using the &quot;<loc href="http://www.w3.org/WAI/GL/WCAG20/TECHS-SUBMIT/">Techniques Submission Form</loc>.&quot;</p>
			<p diff="add">Some techniques contain User Agent and Assistive Technology Support Notes. As time passes, these versions of user agents or assistive technologies may no longer be current, and there is no commitment to update the notes as new versions are released. Authors should test techniques against the user agents and assistive technologies currently available to their users. See also <loc href="conformance" locn-note="uc-accessibility-support-head" linktype="understanding">Understanding Accessibility Support</loc>.</p>
			<p>This document is part of a series of documents published by the W3C Web  Accessibility Initiative (WAI) to support WCAG 2.0. This document was published as a Working Group Note at the same time WCAG 2.0 was published as a W3C Recommendation. Unlike WCAG 2.0, <phrase diff="add">it</phrase> is expected that the information in Understanding WCAG 2.0 will be updated from time to time. See <loc href="http://www.w3.org/WAI/intro/wcag.php">Web Content Accessibility Guidelines (WCAG) Overview</loc> for an introduction to WCAG, supporting technical documents, and educational material.</p> 
		</abstract>
		<langusage>
			<language id="en-US"/>
		</langusage>
		<revisiondesc>
			<p>
				<loc href="/WAI/GL/WCAG20/change-history.html">History of Changes to WCAG 2.0 Working Drafts</loc>
			</p>
		</revisiondesc>
	</header>
	<front>
		<div1 id="intro">
			<head>Introduction to Techniques for WCAG 2.0</head>
			<p>This document is part of a series of documents published by the W3C Web Accessibility Initiative (WAI) to support WCAG 2.0 <bibref ref="WCAG20"></bibref>. It includes a variety of techniques which include specific authoring practices and examples for developing more accessible Web content. As well, it lists failures, which describe common mistakes that are considered failures of WCAG 2.0 Success Criteria.</p>
			<p diff="add">Techniques are specific authoring practices that may be used in support of the WCAG 2.0 success criteria. This document provides "General Techniques" that describe basic practices that are applicable to any technology, and technology-specific techniques that provide information applicable to specific technologies. Technology-specific techniques do not supplant the general techniques: content developers should consider both general techniques and technology-specific techniques as they work toward conformance.</p>
			<p>This is not an introductory document. It is a detailed technical description of techniques that can be used to address the requirements in WCAG 2.0. See <loc href="http://www.w3.org/WAI/intro/wcag.php">Web Content Accessibility Guidelines (WCAG) Overview</loc> for an introduction to WCAG, supporting  technical documents, and educational material.</p>
			<p>In order to make the set of techniques maintained by the WCAG WG as comprehensive as possible, the WCAG WG encourages submission of new techniques so they can be considered for inclusion in this document. Please submit techniques for consideration using the "<loc href="/WAI/GL/WCAG20/TECHS-SUBMIT/">Techniques Submission Form</loc>."</p>
			<div2 id="suff-adv-techs" role="normal">
				<head>Sufficient and Advisory Techniques</head>
				<p>Rather than having technology specific techniques in WCAG 2.0, the guidelines and Success Criteria themselves have been written in a technology neutral fashion. In order to provide guidance and examples for meeting the guidelines using specific technologies (for example HTML) the working group has identified <emph role="bolditalic">sufficient techniques</emph> for each Success Criterion that are sufficient to meet that Success Criterion. <phrase diff="add">Sufficient techniques are provided in a numbered list where each list item provides the technique or combination of techniques that can be used to meet the Success Criterion. When there are multiple techniques on a numbered list item connected by "AND" then all of the techniques must be used. For example, Situation B in Understanding Success Criterion 2.2.1 lists as the third sufficient technique: SCR16: Providing a script that warns the user a time limit is about to expire (Scripting) AND  SCR1: Allowing the user to extend the default time limit  (Scripting).</phrase></p>
			  <p>The list of sufficient techniques is maintained in the "Understanding WCAG 2.0" (and mirrored in How to Meet WCAG 2.0). <phrase diff="chg">By separating the WCAG 2 normative guidelines document from the techniques used to meet the success criteria in those guidelines</phrase> it is possible to update the list as new techniques are discovered, and as Web Technologies and Assistive Technologies progress.</p>
				<p>Note that all techniques are <loc href="informativedef" linktype="glossary">informative</loc>. The "sufficient techniques" are considered sufficient by the WCAG Working Group to meet the success criteria. <phrase diff="chg">However, failure of a test procedure for a sufficient technique does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.</phrase> If techniques are used other than those listed by the Working Group, then some other method for establishing the technique's ability to meet the Success Criteria would be needed.</p>
			  <p>Most Success Criteria have multiple sufficient techniques listed. Any of the listed sufficient techniques can be used to meet the Success Criterion. There may be other techniques which are not documented by the working group that could also meet the Success Criterion. As new sufficient techniques are identified they will be added to the listing.</p>
			  <p>In addition to the sufficient techniques, there are a number of <emph role="bolditalic">advisory techniques</emph> that can enhance accessibility, but did not qualify as sufficient techniques because they are not sufficient to meet the full requirements of the Success Criteria, they are not testable, and/or because they are good and effective techniques in some circumstances but not effective or helpful in others. These are listed as advisory techniques and are right below the sufficient techniques. Authors are encouraged to use these techniques wherever appropriate to increase accessibility of their Web pages.</p>
			  <note diff="add">
			  	<p>Code examples found in the sufficient techniques are intended to demonstrate the principle discussed in the description of the technique. The code is not intended to demonstrate other aspects of accessibility, usability or best coding practices not related to the technique.</p>
			  	<p>All of our techniques assume that people needing special user agents (including AT or special plug-ins) will get and be using that type user agent (eg screen reader, or plug-in that allows keyboard navigation of properly marked up content, etc).</p>
			  </note>
			</div2>
			<div2 id="intro_testing_techs" diff="add">
				<head>Testing Techniques</head>
				<p>Test procedures are provided in techniques to help verify that the technique has been properly implemented. Test procedures do not, however, imply success or failure beyond the particular technique. In particular, test procedures for individual techniques should not be taken as test procedures for the WCAG 2.0 success criteria overall. While the test procedure for a given technique may produce a fail result, because the technique was not used, the success criterion may be met via another technique. It is even possible that the success criterion is met via a technique that is not documented in this collection, so failing test procedures for all documented sufficient techniques may not mean that the success criterion is not met.</p>
				<p>Because of the limited applicability of technique test procedures, they should be used only with caution in conformance evaluation. A passing result for a sufficient technique may indicate that the technique has been successfully applied and therefore the success criterion has been met, but a failing result does not necessarily imply the opposite. By contrast, failure techniques do mean that a failure condition has occurred, in spite of any proper application of sufficient techniques. In this case only, the positive test for the failure technique does indicate that the success criterion is not met, which is a valid result in conformance evaluation.</p>
				<ednote>
					<edtext><loc href="http://www.w3.org/WAI/GL/track/actions/125">ACTION-125</loc> is to gain WG approval of the above text. It has not yet passed that step.</edtext>
				</ednote>
			</div2>
			<div2 id="intro_tech_application" diff="add">
				<head>Application of Techniques</head>
				<p>Techniques in this suite often contain code samples to show the technique in practice. These samples exemplify the technique but do not necessarily exemplify all aspects of good code practice or features needed to conform to other success criteria. This is to keep the examples brief and facilitate understanding of the central point of the sample. Accordingly, authors should not copy these examples in production code unless they provide the missing functionality. In addition to inline code samples, many techniques provide "working examples" that are more complete. Such samples are more appropriate as a starting point for production code, although even these may have minimal content.</p>
				<p>Many techniques describe how to provide alternate mechanisms to access content. It is important to remember that such alternate functionality must itself conform to WCAG 2.0. A given technique may focus on the basic way to provide the alternate mechanism, but authors need to follow additional relevant techniques to ensure the alternate mechanism meets requirements.</p>
				<p>Some techniques use the word "must". Because the techniques document is not a normative document, this word is not used in the sense of RFC 2119. The colloquial use of the word "must" describes proper application of the specific technique under consideration. It does not imply requirements beyond the scope of the technique. This does not mean the technique is required to meet the Success Criterion. Further, the word "should" in the techniques indicates best practice, not a requirement for that technique.</p>
			</div2>
			<div2 id="intro-tech-types" role="normal">
				<head>Technique Collections</head>
				<p>The following list includes links to a series of techniques document collections. </p>
				<!-- This list was created by XSLT, but is generated manually here. -->
				<ulist>
					<item><p><loc href="complete.html">Techniques for WCAG 2.0 (includes all techniques and failures as a single file)</loc></p></item>
					<item><p><loc href="general.html">General Techniques</loc></p></item>
					<item><p><loc href="html.html">HTML and XHTML Techniques</loc></p></item>
					<item><p><loc href="css.html">CSS Techniques</loc></p></item>
					<item><p><loc href="client-side-script.html">Client-side Script Techniques</loc></p></item>
					<item><p><loc href="server-side-script.html">Server-side Script Techniques</loc></p></item>
					<item><p><loc href="smil.html">SMIL Techniques</loc></p></item>
					<item><p><loc href="text.html">Plain Text Techniques</loc></p></item>
					<item><p><loc href="aria.html">WAI-ARIA Techniques</loc></p></item>
					<item><p><loc href="flash.html">Flash Techniques</loc></p></item>
					<item><p><loc href="silverlight.html">Silverlight Techniques</loc></p></item>
					<item><p><loc href="pdf.html">PDF Techniques</loc></p></item>
					<item><p><loc href="failures.html">Common Failures</loc></p></item>
				</ulist>
			</div2>
		</div1>
	</front>
	<body>
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	</body>
	<back>
		<!-- BBC - This is the master list. Some of these refs also appear in the Understanding Doc. -->
		<inform-div1 id="references">
			<head>References</head>
			<blist>
				<bibl id="CSS1" key="CSS1">"Cascading Style Sheets, level 1," B. Bos, H. Wium Lie, eds., W3C Recommendation 17 Dec 1996, revised 11 Jan 1999. Available at <loc href="http://www.w3.org/TR/REC-CSS1/">http://www.w3.org/TR/REC-CSS1/</loc>.</bibl>
				<bibl id="CSS2" key="CSS2">"Cascading Style Sheets, level 2," B. Bos, H. Wium Lie, C. Lilley, and I. Jacobs, eds., W3C Recommendation 12 May 1998. Available at <loc href="http://www.w3.org/TR/CSS2/">http://www.w3.org/TR/CSS2/</loc>.</bibl>
				<bibl id="CSS21" key="CSS21">"Cascading Style Sheets, level 2 revision 1,"  B. Bos, T. Çelik,  I. Hickson,   H. Wium Lie, eds., W3C Candidate Recommendation 25 February 2004.  Available at:  <loc href="http://www.w3.org/TR/CSS21/">http://www.w3.org/TR/CSS21/</loc>
				</bibl>
				<bibl id="CSS3" key="CSS3">
					<titleref href="http://www.w3.org/Style/CSS/current-work">[CSS 2.1 and CSS 3] Roadmap</titleref>, CSS WG's table of modules and publication dates.</bibl>
				<bibl id="FLASH" key="FLASH">"Flash", Adobe Systems. Available at <loc href="http://www.adobe.com/devnet/swf.html">http://www.adobe.com/devnet/swf.html</loc>.</bibl>
				<bibl id="HTML4" key="HTML4">"HTML 4.01 Specification," D. Raggett, A. Le Hors, I. Jacobs, eds.,  W3C Recommendation 24 December 1999. Available at <loc href="http://www.w3.org/TR/html401/">http://www.w3.org/TR/html401/</loc>
				</bibl>
				<bibl id="PDF" key="PDF">"PDF", Adobe Systems. Available at <loc href="http://www.adobe.com/devnet/pdf.html">http://www.adobe.com/devnet/pdf.html</loc>.</bibl>
				<bibl id="WCAG20" key="WCAG20">"Web Content Accessibility Guidelines 2.0,"  B. Caldwell, M Cooper, L Guarino Reid, and G. Vanderheiden, eds., W3 Recommendation 12 December 2008, <loc href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/">http://www.w3.org/TR/2008/REC-WCAG20-20081211</loc>.  The latest version of WCAG 2.0 is available at <loc href="http://www.w3.org/TR/WCAG20/">http://www.w3.org/TR/WCAG20/</loc>.
				</bibl>
				<bibl id="XHTML1" key="XHTML1">"XHTML 1.0 The Extensible HyperText Markup Language (Second Edition)," S. Pemberton, et al.,  W3C Recommendation 26 January 2000, revised 1 August 2002. Available at:  <loc href="http://www.w3.org/TR/xhtml1/">http://www.w3.org/TR/xhtml1/</loc>.</bibl>
			</blist>
		</inform-div1>
	</back>
</spec>
