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Please note that this is only my personal interpretation of WCAG. Secondly, please note that this interpretation has been written specifically with HTML and XHTML in mind, and there are more to the checkpoints than this. Finally, be aware that this article is based on the working draft of 23rd November 2005. As further drafts and/or final recommendations are produced, this article may require amendment. Please check the latest version.

Article sections

  1. Technology Baseline
  2. Design Principles  
  3. Success Criteria  
  4. Conformance Claims  
  5. Single-A Conformance Criteria  
  6. Double-A Conformance Criteria  
  7. Triple-A Conformance Criteria

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Level AAA Conformance Criteria

To conform to WCAG 2.0 level AAA accessibility you need to meet all of the Single-A Conformance Criteria, and all of the Double-A Conformance Criteria, plus the following success criteria:

Success CriterionDescription
1.1.6For pre-recorded multimedia, a combined document containing both captions and audio descriptions is available.
1.2.4Provide sign language interpretation for multimedia. It is not mandated by the guidelines, but in order to avoid confusion and cause further accessibility barriers, it would be important to specify the sign language used — for example, British Sign Language (BSL) is different to American Sign Language (ASL).
1.2.5Provide extended audio descriptions of video for pre-recorded multimedia.
1.3.5Where content is arranged in a sequence that affects its meaning, this sequence should be controlled by markup (e.g. use definition lists, ordered lists etc).
1.3.6Information required to use content does not rely on shape, size, visual location or orientation of components.
1.4.3Text or diagrams and their background must have a luminosity contrast of at least 10:1 (this is a strengthening of 1.4.1). You may wish to use the Juicy Studio Luminosity Contrast Analyser.
1.4.4Audio does not contain background noise, or background noise is at least 20 decibels quieter than foreground content (except for occasional sound effects).
2.1.2All functions are designed to be operated through a keyboard interface (strengthening of 2.1.1).
2.2.4Except for real-time events, timing is not an essential part of activity presented.
2.2.5Interruptions or changes in content can be postponed or suppressed by the user, except in case of an emergency. An emergency is defined as a sudden unexpected occurrence that requires immediate action to preserve health, safety or property. "This offer closes in 10 minutes" or "Hurry up! I want to switch the server off and go home" are not emergencies.
2.2.6When an authenticated session has an inactivity timeout, users may continue without loss of data after re-authenticating.
2.4.6Titles and headings are descriptive and section headings are not repeated (e.g. on a page with multiple sections, don't repeat "section highlights" or "introduction" as a heading).
2.4.7When a page is navigated sequentially, items receive the focus in an order that follows relationships and sequences in the content.
2.4.8Provide a method for the user to determine where they are within the site (breadcrumb trail, site map, indication of current position on navigation menus).
2.5.4Provide context sensitive help for text input.
3.1.3Provide specific definitions where words are used in an unusual or restricted way, or for any jargon. Use <dfn> to provide a definition, provide a glossary of terms, provide a definition in the text or link to an appropriate definition. Useful information about creating a glossary of terms can be found on A List Apart.
3.1.4Provide a mechanism for finding the expanded form of any abbreviation or acronym. Any of the following methods are deemed to be appropriate:
  1. link to a glossary page.
  2. link to the appropriate part of an online dictionary.
  3. provide the expanded form on first use on the page, immediately followed by the abbreviation.
  4. provide an example instead of a definition if this would be more helpful.
  5. link to a definition elsewhere on the page.
  6. use <abbr> or <acronym> to specify a title for expansion.
Note that currently the <abbr> element is not supported by Internet Explorer. The word "acronym" is commonly used to indicate an abbreviation formed from the initial letters of the expanded word (FBI, radar). Some sources suggest that unless this formed abbreviation is pronounced as a word rather than distinct letters (e.g. radar but not FBI), then the correct term is an initialism — although this has rather fallen from common usage. The W3C use FBI as an example of an acronym, so it seems reasonable that the common-usage definition "a word formed from the initial or significant letters of a series of other words" is fine.
3.1.5Where text requires reading ability more advanced than "lower secondary education" (in the UK this equates to an upper limit of around 16 years old; study at ages 16-19 is usually referred to as "upper secondary") you should provide a spoken alternative, graphics or diagrams to illustrate difficult concepts, or a text summary suitable for lower secondary reading ability.
3.1.6Where a page is navigated sequentially, elements receive focus in an order that follows relationships and sequences within the content. This appears to me to be an exact and unnecessary duplication of criterion 2.4.7.
3.2.5Changes of context/information are only initiated by user request — do not automatically update content, instead provide a mechanism to request updated content; implement redirects server side; do not open unrequested new windows or popups; do not open popups when an input field is selected; do not use the onblur event to change content, do not use an automatic update that cannot be disabled and do not open a popup or change the window after a click/selection of what appears to be normal text rather than a hyperlink.
4.2.7Regardless of whether or not the technology baseline is satisfied, the content satisfies all level 1 and 2 success criteria.