Web Content Accessibility Guidelines (WCAG) 2.0 [ contents This version: http://www.w3.org/TR/2008/REC-WCAG20-20081211/ Latest version: http://www.w3.org/TR/WCAG20/ Previous version: http://www.w3.org/TR/2008/PR-WCAG20-20081103/ Editors: Ben Caldwell, Trace R&D Center, University of Wisconsin-Madison Michael Cooper, W3C Loretta Guarino Reid, Google, Inc. Gregg Vanderheiden, Trace R&D Center, University of Wisconsin-Madison Previous Editors: Wendy Chisholm (until July 2006 while at W3C) John Slatin (until June 2006 while at Accessibility Institute, University of Texas at Austin) Jason White (until June 2005 while at University of Melbourne) Please refer to the errata See also translations This document is also available in non-normative formats, available from Alternate Versions of Web Content Accessibility Guidelines 2.0 Copyright W3C ® MIT ERCIM Keio liability trademark document use Web Content Accessibility Guidelines (WCAG) 2.0 covers a wide range of recommendations for making Web content more accessible. Following these guidelines will make content accessible to a wider range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, photosensitivity and combinations of these. Following these guidelines will also often make your Web content more usable to users in general. WCAG 2.0 success criteria are written as testable statements that are not technology-specific. Guidance about satisfying the success criteria in specific technologies, as well as general information about interpreting the success criteria, is provided in separate documents. See Web Content Accessibility Guidelines (WCAG) Overview WCAG 2.0 succeeds Web Content Accessibility Guidelines 1.0 [WCAG10] 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 W3C technical reports index http://www.w3.org/TR/ This is the Web Content Accessibility Guidelines (WCAG) 2.0 W3C Recommendation Web Content Accessibility Guidelines Working Group This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web. WCAG 2.0 is supported by the associated non-normative documents, Understanding WCAG 2.0 Techniques for WCAG 2.0 The Working Group requests that any comments be made using the provided online comment form [email protected] archives for the public comments list WCAG WG mailing list discussions This document has been produced as part of the W3C Web Accessibility Initiative WCAG Working Group charter WAI Technical Activity This document was produced by a group operating under the 5 February 2004 W3C Patent Policy public list of any patent disclosures Essential Claim(s) section 6 of the W3C Patent Policy Introduction WCAG 2.0 Layers of Guidance WCAG 2.0 Supporting Documents Important Terms in WCAG 2.0 WCAG 2.0 Guidelines 1 Perceivable 1.1 Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language. 1.2 Provide alternatives for time-based media. 1.3 Create content that can be presented in different ways (for example simpler layout) without losing information or structure. 1.4 Make it easier for users to see and hear content including separating foreground from background. 2 Operable 2.1 Make all functionality available from a keyboard. 2.2 Provide users enough time to read and use content. 2.3 Do not design content in a way that is known to cause seizures. 2.4 Provide ways to help users navigate, find content, and determine where they are. 3 Understandable 3.1 Make text content readable and understandable. 3.2 Make Web pages appear and operate in predictable ways. 3.3 Help users avoid and correct mistakes. 4 Robust 4.1 Maximize compatibility with current and future user agents, including assistive technologies. Conformance Conformance Requirements Conformance Claims (Optional) Statement of Partial Conformance - Third Party Content Statement of Partial Conformance - Language Appendix A: Glossary Appendix B: Acknowledgments Appendix C: References This section is informative Web Content Accessibility Guidelines (WCAG) 2.0 defines how to make Web content more accessible to people with disabilities. Accessibility involves a wide range of disabilities, including visual, auditory, physical, speech, cognitive, language, learning, and neurological disabilities. Although these guidelines cover a wide range of issues, they are not able to address the needs of people with all types, degrees, and combinations of disability. These guidelines also make Web content more usable by older individuals with changing abilities due to aging and often improve usability for users in general. WCAG 2.0 is developed through the W3C process [WCAG10] Web Content Accessibility Guidelines (WCAG) Overview Web accessibility depends not only on accessible content but also on accessible Web browsers and other user agents. Authoring tools also have an important role in Web accessibility. For an overview of how these components of Web development and interaction work together, see: Essential Components of Web Accessibility User Agent Accessibility Guidelines (UAAG) Overview Authoring Tool Accessibility Guidelines (ATAG) Overview The individuals and organizations that use WCAG vary widely and include Web designers and developers, policy makers, purchasing agents, teachers, and students. In order to meet the varying needs of this audience, several layers of guidance are provided including overall principles guidelines success criteria sufficient techniques, advisory techniques documented common failures Principles perceivable, operable, understandable, and robust Understanding the Four Principles of Accessibility Guidelines Success Criteria Understanding Levels of Conformance Sufficient and Advisory Techniques guidelines success criteria techniques sufficient advisory Sufficient and Advisory Techniques in Understanding WCAG 2.0 All of these layers of guidance (principles, guidelines, success criteria, and sufficient and advisory techniques) work together to provide guidance on how to make content more accessible. Authors are encouraged to view and apply all layers that they are able to, including the advisory techniques, in order to best address the needs of the widest possible range of users. Note that even content that conforms at the highest level (AAA) will not be accessible to individuals with all types, degrees, or combinations of disability, particularly in the cognitive language and learning areas. Authors are encouraged to consider the full range of techniques, including the advisory techniques, as well as to seek relevant advice about current best practice to ensure that Web content is accessible, as far as possible, to this community. Metadata The WCAG 2.0 document is designed to meet the needs of those who need a stable, referenceable technical standard. Other documents, called supporting documents, are based on the WCAG 2.0 document and address other important purposes, including the ability to be updated to describe how WCAG would be applied with new technologies. Supporting documents include: How to Meet WCAG 2.0 Understanding WCAG 2.0 Techniques for WCAG 2.0 The WCAG 2.0 Documents See Web Content Accessibility Guidelines (WCAG) Overview Additional resources covering topics such as the business case for Web accessibility, planning implementation to improve the accessibility of Web sites, and accessibility policies are listed in WAI Resources WCAG 2.0 includes three important terms that are different from WCAG 1.0. Each of these is introduced briefly below and defined more fully in the glossary. Web Page It is important to note that, in this standard, the term " Web page Understanding "Web Page" Programmatically Determined Several success criteria require that content (or certain aspects of content) can be " programmatically determined user agents assistive technologies Understanding Programmatically Determined Accessibility Supported Using a technology in a way that is accessibility supported means that it works with assistive technologies (AT) and the accessibility features of operating systems, browsers, and other user agents. Technology features can only be relied upon accessibility supported The definition of "accessibility supported" is provided in the Appendix A: Glossary Understanding Accessibility Support This section is normative Understanding Guideline 1.1 1.1.1 Non-text Content: non-text content text alternative Controls, Input: name Guideline 4.1 Time-Based Media: Guideline 1.2 Test: text Sensory: specific sensory experience CAPTCHA Decoration, Formatting, Invisible: pure decoration assistive technology How to Meet 1.1.1 | Understanding 1.1.1 Understanding Guideline 1.2 1.2.1 Audio-only and Video-only (Prerecorded): prerecorded audio-only video-only media alternative for text Prerecorded Audio-only: alternative for time-based media Prerecorded Video-only: How to Meet 1.2.1 | Understanding 1.2.1 1.2.2 Captions (Prerecorded): Captions prerecorded audio synchronized media media alternative for text How to Meet 1.2.2 | Understanding 1.2.2 1.2.3 Audio Description or Media Alternative (Prerecorded): alternative for time-based media audio description prerecorded video synchronized media media alternative for text How to Meet 1.2.3 | Understanding 1.2.3 1.2.4 Captions (Live): Captions live audio synchronized media How to Meet 1.2.4 | Understanding 1.2.4 1.2.5 Audio Description (Prerecorded): Audio description prerecorded video synchronized media How to Meet 1.2.5 | Understanding 1.2.5 1.2.6 Sign Language (Prerecorded): Sign language interpretation prerecorded audio synchronized media How to Meet 1.2.6 | Understanding 1.2.6 1.2.7 Extended Audio Description (Prerecorded): audio descriptions extended audio description prerecorded video synchronized media How to Meet 1.2.7 | Understanding 1.2.7 1.2.8 Media Alternative (Prerecorded): alternative for time-based media prerecorded synchronized media video-only How to Meet 1.2.8 | Understanding 1.2.8 1.2.9 Audio-only (Live): alternative for time-based media live audio-only How to Meet 1.2.9 | Understanding 1.2.9 Understanding Guideline 1.3 1.3.1 Info and Relationships: structure relationships presentation programmatically determined How to Meet 1.3.1 | Understanding 1.3.1 1.3.2 Meaningful Sequence: correct reading sequence programmatically determined How to Meet 1.3.2 | Understanding 1.3.2 1.3.3 Sensory Characteristics: Note: Guideline 1.4 How to Meet 1.3.3 | Understanding 1.3.3 Understanding Guideline 1.4 1.4.1 Use of Color: Note: Guideline 1.3 How to Meet 1.4.1 | Understanding 1.4.1 1.4.2 Audio Control: mechanism Note: Conformance Requirement 5: Non-Interference How to Meet 1.4.2 | Understanding 1.4.2 1.4.3 Contrast (Minimum): The visual presentation of text images of text contrast ratio 4. Large Text: Large-scale Incidental: user interface component pure decoration Logotypes: How to Meet 1.4.3 | Understanding 1.4.3 1.4.4 Resize text: captions images of text text assistive technology How to Meet 1.4.4 | Understanding 1.4.4 1.4.5 Images of Text: text images of text Customizable: visually customized Essential: essential Note: How to Meet 1.4.5 | Understanding 1.4.5 1.4.6 Contrast (Enhanced): The visual presentation of text images of text contrast ratio Large Text: Large-scale 4. Incidental: user interface component pure decoration Logotypes: How to Meet 1.4.6 | Understanding 1.4.6 1.4.7 Low or No Background Audio: prerecorded audio-only CAPTCHA No Background: Turn Off: 20 dB: Note: How to Meet 1.4.7 | Understanding 1.4.7 1.4.8 Visual Presentation: blocks of text mechanism Foreground and background colors can be selected by the user. Width is no more than 80 characters or glyphs (40 if CJK Text is not justified (aligned to both the left and the right margins). Line spacing (leading) is at least space-and-a-half within paragraphs, and paragraph spacing is at least 1.5 times larger than the line spacing. Text can be resized without assistive technology up to 200 percent in a way that does not require the user to scroll horizontally to read a line of text on a full-screen window How to Meet 1.4.8 | Understanding 1.4.8 1.4.9 Images of Text (No Exception): Images of text pure decoration text essential Note: How to Meet 1.4.9 | Understanding 1.4.9 Understanding Guideline 2.1 2.1.1 Keyboard: functionality keyboard interface Note 1: Note 2: How to Meet 2.1.1 | Understanding 2.1.1 2.1.2 No Keyboard Trap: keyboard interface Note: Conformance Requirement 5: Non-Interference How to Meet 2.1.2 | Understanding 2.1.2 2.1.3 Keyboard (No Exception): functionality keyboard interface How to Meet 2.1.3 | Understanding 2.1.3 Understanding Guideline 2.2 2.2.1 Timing Adjustable: Turn off: Adjust: Extend: Real-time Exception: Essential Exception: essential 20 Hour Exception: Note: Success Criterion 3.2.1 How to Meet 2.2.1 | Understanding 2.2.1 2.2.2 Pause, Stop, Hide: blinking Moving, blinking, scrolling: pause essential Auto-updating: Note 1: Guideline 2.3 Note 2: Conformance Requirement 5: Non-Interference Note 3: Note 4: How to Meet 2.2.2 | Understanding 2.2.2 2.2.3 No Timing: essential synchronized media real-time events How to Meet 2.2.3 | Understanding 2.2.3 2.2.4 Interruptions: emergency How to Meet 2.2.4 | Understanding 2.2.4 2.2.5 Re-authenticating: How to Meet 2.2.5 | Understanding 2.2.5 Understanding Guideline 2.3 2.3.1 Three Flashes or Below Threshold: Web pages flash general flash and red flash thresholds Note: Conformance Requirement 5: Non-Interference How to Meet 2.3.1 | Understanding 2.3.1 2.3.2 Three Flashes: Web pages flashes How to Meet 2.3.2 | Understanding 2.3.2 Understanding Guideline 2.4 2.4.1 Bypass Blocks: mechanism Web pages How to Meet 2.4.1 | Understanding 2.4.1 2.4.2 Page Titled: Web pages How to Meet 2.4.2 | Understanding 2.4.2 2.4.3 Focus Order: Web page navigated sequentially How to Meet 2.4.3 | Understanding 2.4.3 2.4.4 Link Purpose (In Context): purpose of each link programmatically determined link context ambiguous to users in general How to Meet 2.4.4 | Understanding 2.4.4 2.4.5 Multiple Ways: Web page set of Web pages process How to Meet 2.4.5 | Understanding 2.4.5 2.4.6 Headings and Labels: labels How to Meet 2.4.6 | Understanding 2.4.6 2.4.7 Focus Visible: How to Meet 2.4.7 | Understanding 2.4.7 2.4.8 Location: set of Web pages How to Meet 2.4.8 | Understanding 2.4.8 2.4.9 Link Purpose (Link Only): mechanism ambiguous to users in general How to Meet 2.4.9 | Understanding 2.4.9 2.4.10 Section Headings: Section Note 1: Note 2: user interface components Success Criterion 4.1.2 How to Meet 2.4.10 | Understanding 2.4.10 Understanding Guideline 3.1 3.1.1 Language of Page: human language Web page programmatically determined How to Meet 3.1.1 | Understanding 3.1.1 3.1.2 Language of Parts: human language programmatically determined How to Meet 3.1.2 | Understanding 3.1.2 3.1.3 Unusual Words: mechanism used in an unusual or restricted way idioms jargon How to Meet 3.1.3 | Understanding 3.1.3 3.1.4 Abbreviations: mechanism abbreviations How to Meet 3.1.4 | Understanding 3.1.4 3.1.5 Reading Level: lower secondary education level supplemental content How to Meet 3.1.5 | Understanding 3.1.5 3.1.6 Pronunciation: mechanism How to Meet 3.1.6 | Understanding 3.1.6 Understanding Guideline 3.2 3.2.1 On Focus: change of context How to Meet 3.2.1 | Understanding 3.2.1 3.2.2 On Input: user interface component change of context How to Meet 3.2.2 | Understanding 3.2.2 3.2.3 Consistent Navigation: Web pages set of Web pages same relative order How to Meet 3.2.3 | Understanding 3.2.3 3.2.4 Consistent Identification: same functionality Web pages How to Meet 3.2.4 | Understanding 3.2.4 3.2.5 Change on Request: Changes of context mechanism How to Meet 3.2.5 | Understanding 3.2.5 Understanding Guideline 3.3 3.3.1 Error Identification: input error How to Meet 3.3.1 | Understanding 3.3.1 3.3.2 Labels or Instructions: Labels How to Meet 3.3.2 | Understanding 3.3.2 3.3.3 Error Suggestion: input error How to Meet 3.3.3 | Understanding 3.3.3 3.3.4 Error Prevention (Legal, Financial, Data): Web pages legal commitments user-controllable Reversible: Checked: input errors Confirmed: mechanism How to Meet 3.3.4 | Understanding 3.3.4 3.3.5 Help: Context-sensitive help How to Meet 3.3.5 | Understanding 3.3.5 3.3.6 Error Prevention (All): Web pages Reversible: Checked: input errors Confirmed: mechanism How to Meet 3.3.6 | Understanding 3.3.6 Understanding Guideline 4.1 4.1.1 Parsing: Note: How to Meet 4.1.1 | Understanding 4.1.1 4.1.2 Name, Role, Value: user interface components name role programmatically determined programmatically set user agents assistive technologies Note: How to Meet 4.1.2 | Understanding 4.1.2 This section is normative This section lists requirements for conformance accessibility supported relied upon Understanding Conformance In order for a Web page to conform to WCAG 2.0, all of the following conformance requirements must be satisfied: 1. Conformance Level: Level A: Web page satisfies conforming alternate version Level AA: Level AAA: Note 1: Note 2: 2. Full pages: Conformance Web page(s) Note 1: Note 2: Authors of Statement of Partial Conformance 3. Complete processes: Web page process Example: 4. Only Accessibility-Supported Ways of Using Technologies: accessibility-supported technologies relied upon Understanding accessibility support 5. Non-Interference: technologies accessibility supported Web page when any technology that is not relied upon when any technology that is not relied upon is turned off in a user agent, and when any technology that is not relied upon is not supported by a user agent In addition, the following success criteria apply to all content on the page, including content that is not otherwise relied upon to meet conformance, because failure to meet them could interfere with any use of the page: 1.4.2 - Audio Control 2.1.2 - No Keyboard Trap 2.3.1 - Three Flashes or Below Threshold 2.2.2 - Pause, Stop, Hide Note: For more information, including examples, see Understanding Conformance Requirements Conformance is defined only for Web pages Conformance claims are not required must Date Guidelines title, version and URI http://www.w3.org/TR/2008/REC-WCAG20-20081211/ Conformance level A concise description of the Web pages Note 1: Note 2: A list of the Web content technologies relied upon Note: In addition to the required components of a conformance claim above, consider providing additional information to assist users. Recommended additional information includes: A list of success criteria beyond the level of conformance claimed that have been met. This information should be provided in a form that users can use, preferably machine-readable metadata. A list of the specific technologies that are " used but not relied upon A list of user agents, including assistive technologies that were used to test the content. Information about any additional steps taken that go beyond the success criteria to enhance accessibility. A machine-readable metadata version of the list of specific technologies that are relied upon A machine-readable metadata version of the conformance claim. Note 1: Understanding Conformance Claims Note 2: Understanding Metadata Sometimes, Web pages are created that will later have additional content added to them. For example, an email program, a blog, an article that allows users to add comments, or applications supporting user-contributed content. Another example would be a page, such as a portal or news site, composed of content aggregated from multiple contributors, or sites that automatically insert content from other sources over time, such as when advertisements are inserted dynamically. In these cases, it is not possible to know at the time of original posting what the uncontrolled content of the pages will be. It is important to note that the uncontrolled content can affect the accessibility of the controlled content as well. Two options are available: A determination of conformance can be made based on best knowledge. If a page of this type is monitored and repaired (non-conforming content is removed or brought into conformance) within two business days, then a determination or claim of conformance can be made since, except for errors in externally contributed content which are corrected or removed when encountered, the page conforms. No conformance claim can be made if it is not possible to monitor or correct non-conforming content; OR A "statement of partial conformance" may be made that the page does not conform, but could conform if certain parts were removed. The form of that statement would be, "This page does not conform, but would conform to WCAG 2.0 at level X if the following parts from uncontrolled sources were removed." In addition, the following would also be true of uncontrolled content that is described in the statement of partial conformance: It is not content that is under the author's control. It is described in a way that users can identify (e.g., they cannot be described as "all parts that we do not control" unless they are clearly marked as such.) A "statement of partial conformance due to language" may be made when the page does not conform, but would conform if accessibility support does not conform, but This section is normative shortened form of a word, phrase, or name where the abbreviation has not become part of the language Note 1: initialisms Note 1: Example 1: Société Nationale des Chemins de Fer Example 2: acronyms Example: Note 2: supported by users' assistive technologies user agents To qualify as an accessibility-supported use of a Web content technology (or feature of a technology), both 1 and 2 must be satisfied for a Web content technology (or feature): The way that the Web content technology human language(s) AND The Web content technology must have accessibility-supported user agents that are available to users. The technology is supported natively in widely-distributed user agents that are also accessibility supported (such as HTML and CSS); OR The technology is supported in a widely-distributed plug-in that is also accessibility supported; OR The content is available in a closed environment, such as a university or corporate network, where the user agent required by the technology and used by the organization is also accessibility supported; OR The user agent(s) that support the technology are accessibility supported and are available for download or purchase in a way that: does not cost a person with a disability any more than a person without a disability and is as easy to find and obtain for a person with a disability as it is for a person without disabilities. Note 1: Level of Assistive Technology Support Needed for "Accessibility Support" Note 2: relied upon Conformance Requirement 4: Only Accessibility-Supported Ways of Using Technologies Conformance Requirement 5: Non-Interference Note 3: Web Technology Note 4: Note 5: Understanding Accessibility-Supported Web Technology Uses document including correctly sequenced text descriptions of time-based visual and auditory information and providing a means for achieving the outcomes of any time-based interaction Note: the purpose cannot be determined from the link and all information of the Web page presented to the user simultaneously with the link (i.e., readers without disabilities would not know what a link would do until they activated it) Example: picture created by a spatial arrangement of characters or glyphs (typically from the 95 printable characters defined by ASCII). hardware and/or software that acts as a user agent Note 1: Note 2: APIs Note 3: Example: screen magnifiers, and other visual reading assistants, which are used by people with visual, perceptual and physical print disabilities to change text font, size, spacing, color, synchronization with speech, etc. in order to improve the visual readability of rendered text and images; screen readers, which are used by people who are blind to read textual information through synthesized speech or braille; text-to-speech software, which is used by some people with cognitive, language, and learning disabilities to convert text into synthetic speech; speech recognition software, which may be used by people who have some physical disabilities; alternative keyboards, which are used by people with certain physical disabilities to simulate the keyboard (including alternate keyboards that use head pointers, single switches, sip/puff and other special input devices.); alternative pointing devices, which are used by people with certain physical disabilities to simulate mouse pointing and button activations. the technology of sound reproduction Note: narration added to the soundtrack to describe important visual details that cannot be understood from the main soundtrack alone Note 1: video Note 2: extended audio description Note 3: video audio Note 4: a time-based presentation that contains only audio video switch back and forth between two visual states in a way that is meant to draw attention Note: flash more than one sentence of text initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart" Note 1: Note 2: [CAPTCHA] synchronized visual and/or text alternative Note 1: Note 2: Note 3: images of text video Note 4: Note 5: Note 6: Audio descriptions major changes in the content of the Web page Changes in context include changes of: user agent viewport focus; content Web page Note: Example: satisfying all the requirements of a given standard, guideline or specification version that conforms at the designated level, and provides all of the same information and functionality human language is as up to date as the non-conforming content, and for which at least one of the following is true: the conforming version can be reached from the non-conforming page via an accessibility-supported mechanism the non-conforming version can only be reached from the conforming version, or the non-conforming version can only be reached from a conforming page that also provides a mechanism to reach the conforming version Note 1: Note 2: Note 3: Note 4: conformance requirement 1 Note 5: Note 6: supplementary content Note 7: See Understanding Conforming Alternate Versions information and sensory experience to be communicated to the user by means of a user agent structure presentation help text that provides information related to the function currently being performed Note: (L1 + 0.05) / (L2 + 0.05), where L1 is the relative luminance L2 is the relative luminance Note 1: Note 2: Note 3: Note 4: Note 5: Note 6: any sequence where words and paragraphs are presented in an order that does not change the meaning of the content a sudden, unexpected situation or occurrence that requires immediate action to preserve health, safety, or property if removed, would fundamentally change the information or functionality of the content, and audio description that is added to an audiovisual presentation by pausing the video Note: video audio description a pair of opposing changes in relative luminance Note 1: general flash and red flash thresholds Note 2: blinking processes a flash passes there are no more than three general flashes red flashes the combined area of flashes occurring concurrently occupies no more than a total of .006 steradians within any 10 degree visual field on the screen (25% of any 10 degree visual field on the screen) at typical viewing distance where: A general flash relative luminance A red flash Exception: Note 1: Note 2: Note 3: "pair of opposing transitions involving a saturated red" [HARDING-BINNIE] Note 4: language that is spoken, written or signed (through visual or tactile means) to communicate with humans Note: sign language phrase whose meaning cannot be deduced from the meaning of the individual words and the specific words cannot be changed without losing the meaning Note: Example 1: Example 2: さじを投げる Example 3: Hij ging met de kippen op stok text that has been rendered in a non-text form (e.g., an image) in order to achieve a particular visual effect Note: text Example: for information purposes and not required for conformance Note: conformance normative information provided by the user that is not accepted Note: Information that is required by the Web page Information that is provided by the user but that falls outside the required data format or values words used in a particular way by people in a particular field Example: interface used by software to obtain keystroke input Note 1: Example: Note 2: text text alternative content Note 1: name Note 2: with at least 18 point or 14 point bold or font size that would yield equivalent size for Chinese, Japanese and Korean (CJK) fonts Note 1: Note 2: Note 3: Note 4: Note 5: transactions where the person incurs a legally binding obligation or benefit Example: nature of the result obtained by activating a hyperlink information captured from a real-world event and transmitted to the receiver with no more than a broadcast delay Note 1: Note 2: the two or three year period of education that begins after completion of six years of school and ends nine years after the beginning of primary education Note: [UNESCO] process Note 1: relied upon user agents assistive technologies Note 2: media that presents no more information than is already presented in text (directly or via text alternatives) Note: text by which software can identify a component within Web content to the user Note 1: label Note 2: navigated in the order defined for advancing focus (from one element to the next) using a keyboard interface any content that is not a sequence of characters that can be programmatically determined human language Note: ASCII Art required for conformance Note 1: Note 2: informative on the most common sized desktop/laptop display with the viewport maximized Note: stopped by user request and not resumed until requested by user information that is not live rendering of the content six year time period that begins between the ages of five and seven, possibly without any previous education Note: [UNESCO] series of user actions where each action is required in order to complete an activity Example 1: Example 2: determined by software from author-supplied data provided in a way that different user agents assistive technologies Example 1: Example 2: API additional information that can be programmatically determined relationships Example: Note: set by software using methods that are supported by user agents, including assistive technologies serving only an aesthetic purpose, providing no information, and having no functionality Note: Example: event that a) occurs at the same time as the viewing and b) is not completely generated by the content Example 1: Example 2: Example 3: meaningful associations between distinct pieces of content the relative brightness of any point in a colorspace, normalized to 0 for darkest black and 1 for lightest white Note 1: R G B R G B if R sRGB R sRGB R sRGB if G sRGB G sRGB G sRGB if B sRGB B sRGB B sRGB and R sRGB sRGB sRGB R sRGB 8bit G sRGB 8bit B sRGB 8bit The "^" character is the exponentiation operator. (Formula taken from [sRGB] [IEC-4WD] Note 2: Understanding Success Criterion 1.4.3 Note 3: Note 4: Note 5: MathML version of the relative luminance definition the content would not conform technology text or number by which software can identify the function of a component within Web content Example: same result when used Example: same position relative to other items Note: the success criterion does not evaluate to 'false' when applied to the page A self-contained portion of written content that deals with one or more related topics or thoughts Note: collection of Web pages Note: a language using combinations of movements of the hands and arms, facial expressions, or body positions to convey meaning translation of one language, generally a spoken language, into a sign language Note: a sensory experience that is not purely decorative and does not primarily convey important information or perform a function Example: The way the parts of a Web page The way a collection of Web pages additional content Example 1: Web page Example 2: process Example 3: audio video media alternative for text mechanism user agents Note 1: Note 2: Example: HTML CSS SVG PNG PDF sequence of characters that can be programmatically determined human language Text non-text content Example: Note: Understanding Text Alternatives words used in such a way that requires users to know exactly which definition to apply in order to understand the content correctly Example: any software that retrieves and presents Web content for users Example: assistive technologies data that is intended to be accessed by users Note: Example: a part of the content that is perceived by users as a single control for a distinct function Note 1: Note 2: Example: the technology of moving or sequenced pictures or images Note: a time-based presentation that contains only video audio object in which the user agent presents content Note 1: user agent Note 2: User Agent Accessibility Guidelines 1.0 Glossary the font, size, color, and background can be set a non-embedded resource obtained from a single URI using HTTP plus any other resources that are used in the rendering or intended to be rendered together with it by a user agent Note 1: Note 2: Example 1: Example 2: Example 3: Example 4: This section is informative This publication has been funded in part with Federal funds from the U.S. Department of Education, National Institute on Disability and Rehabilitation Research (NIDRR) under contract number ED05CO0039. The content of this publication does not necessarily reflect the views or policies of the U.S. Department of Education, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. Additional information about participation in the Web Content Accessibility Guidelines Working Group (WCAG WG) can be found on the Working Group home page Bruce Bailey (U.S. Access Board) Frederick Boland (NIST) Ben Caldwell (Trace R&D Center, University of Wisconsin) Sofia Celic (W3C Invited Expert) Michael Cooper (W3C) Roberto Ellero (International Webmasters Association / HTML Writers Guild) Bengt Farre (Rigab) Loretta Guarino Reid (Google) Katie Haritos-Shea Andrew Kirkpatrick (Adobe) Drew LaHart (IBM) Alex Li (SAP AG) David MacDonald (E-Ramp Inc.) Roberto Scano (International Webmasters Association / HTML Writers Guild) Cynthia Shelly (Microsoft) Andi Snow-Weaver (IBM) Christophe Strobbe (DocArch, K.U.Leuven) Gregg Vanderheiden (Trace R&D Center, University of Wisconsin) Shadi Abou-Zahra, Jim Allan, Jenae Andershonis, Avi Arditti, Aries Arditi, Mike Barta, Sandy Bartell, Kynn Bartlett, Marco Bertoni, Harvey Bingham, Chris Blouch, Paul Bohman, Patrice Bourlon, Judy Brewer, Andy Brown, Dick Brown, Doyle Burnett, Raven Calais, Tomas Caspers, Roberto Castaldo, Sambhavi Chandrashekar, Mike Cherim, Jonathan Chetwynd, Wendy Chisholm, Alan Chuter, David M Clark, Joe Clark, James Coltham, James Craig, Tom Croucher, Nir Dagan, Daniel Dardailler, Geoff Deering, Pete DeVasto, Don Evans, Neal Ewers, Steve Faulkner, Lainey Feingold, Alan J. Flavell, Nikolaos Floratos, Kentarou Fukuda, Miguel Garcia, P.J. Gardner, Greg Gay, Becky Gibson, Al Gilman, Kerstin Goldsmith, Michael Grade, Jon Gunderson, Emmanuelle Gutiérrez y Restrepo, Brian Hardy, Eric Hansen, Sean Hayes, Shawn Henry, Hans Hillen, Donovan Hipke, Bjoern Hoehrmann, Chris Hofstader, Yvette Hoitink, Carlos Iglesias, Ian Jacobs, Phill Jenkins, Jyotsna Kaki, Leonard R. Kasday, Kazuhito Kidachi, Ken Kipness, Marja-Riitta Koivunen, Preety Kumar, Gez Lemon, Chuck Letourneau, Scott Luebking, Tim Lacy, Jim Ley, William Loughborough, Greg Lowney, Luca Mascaro, Liam McGee, Jens Meiert, Niqui Merret, Alessandro Miele, Mathew J Mirabella, Charles McCathieNevile , Matt May, Marti McCuller, Sorcha Moore, Charles F. Munat, Robert Neff, Bruno von Niman, Tim Noonan, Sebastiano Nutarelli, Graham Oliver, Sean B. Palmer, Sailesh Panchang, Nigel Peck, Anne Pemberton, David Poehlman, Adam Victor Reed, Chris Ridpath, Lee Roberts, Gregory J. Rosmaita, Matthew Ross, Sharron Rush, Gian Sampson-Wild, Joel Sanda, Gordon Schantz, Lisa Seeman, John Slatin, Becky Smith, Jared Smith, Neil Soiffer, Jeanne Spellman, Mike Squillace, Michael Stenitzer, Jim Thatcher, Terry Thompson, Justin Thorp, Makoto Ueki, Eric Velleman, Dena Wainwright, Paul Walsch, Takayuki Watanabe, Jason White. This section is informative The CAPTCHA Project, Carnegie Mellon University. The project is online at http://www.captcha.net Harding G. F. A. and Binnie, C.D., Independent Analysis of the ITC Photosensitive Epilepsy Calibration Test Tape. 2002. IEC/4WD 61966-2-1: Colour Measurement and Management in Multimedia Systems and Equipment - Part 2.1: Default Colour Space - sRGB. May 5, 1998. "A Standard Default Color Space for the Internet - sRGB," M. Stokes, M. Anderson, S. Chandrasekar, R. Motta, eds., Version 1.10, November 5, 1996. A copy of this paper is available at http://www.w3.org/Graphics/Color/sRGB.html International Standard Classification of Education, 1997. A copy of the standard is available at http://www.unesco.org/education/information/nfsunesco/doc/isced_1997.htm Web Content Accessibility Guidelines 1.0, G. Vanderheiden, W. Chisholm, I. Jacobs, Editors, W3C Recommendation, 5 May 1999, http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/. The latest version of WCAG 1.0 is available at http://www.w3.org/TR/WAI-WEBCONTENT/