Monday, February 26, 2007

WCAG

Web Content Accessibility Guidelines (WCAG) are part of a series of Web accessibility guidelines published by the W3C's Web Accessibility Initiative (WAI). They consist of a set of guidelines on making content accessible, primarily for disabled users, but also for all user agents, including highly limited devices, such as mobile phones.

Web "content" generally refers to the information in a Web page or Web application, including text, images, forms, sounds, and such. More specific definitions are available in the WCAG documents.

WCAG technical documents are developed by the Web Content Accessibility Guidelines Working Group (WCAG WG), which is part of the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI). Other accessibility guidelines include the Authoring Tool Accessibility Guidelines (ATAG) and the User Agent Accessibility Guidelines (UAAG).

The WCAG are intended for all Web content developers (page authors and site designers) and for developers of authoring tools. Following them will make Web content more available to all users, whatever user agent they are using (desktop browser, voice browser, mobile phone, etc.) or constraints they may be operating under (noisy surroundings, hands-free environment, etc.). These guidelines do not discourage content developers from using images, video, etc., but rather explain how to make multimedia content more accessible to a wide audience.

There are currently two versions of the WCAG. WCAG 1, contains 14 main guidelines with a total of 65 in all. WCAG 2, has reorganized and combined many of the WCAG 1 guidelines to create 21 new ones.

Each guideline has a one or more ‘checkpoints’ which developers should consider to ensure the accessibility of a Web page. Each checkpoint has a priority level based on its impact on Web accessibility. The WCAG provides a number of examples and techniques to help Web developers to implement the guidelines.

WCAG Priority Levels

Each checkpoint has a priority level assigned by the Working Group based on the checkpoint's impact on accessibility:

[Priority 1]
A Web content developer must satisfy this checkpoint. Otherwise, one or more groups will find it impossible to access information in the document. Satisfying this checkpoint is a basic requirement for some groups to be able to use Web documents.

[Priority 2]
A Web content developer should satisfy this checkpoint. Otherwise, one or more groups will find it difficult to access information in the document. Satisfying this checkpoint will remove significant barriers to accessing Web documents.

[Priority 3]
A Web content developer may address this checkpoint. Otherwise, one or more groups will find it somewhat difficult to access information in the document. Satisfying this checkpoint will improve access to Web documents.

WCAG Conformance

The WCAG guidelines have three levels of conformance:

Conformance Level "A": all Priority 1 checkpoints are satisfied. This is known as 'WCAG A' compliant.

Conformance Level "Double-A": all Priority 1 and 2 checkpoints are satisfied. This is known as 'WCAG AA' compliant.

Conformance Level "Triple-A": all Priority 1, 2, and 3 checkpoints are satisfied. This is known as 'WCAG AAA' compliant.

Note that conformance levels are even spelled out in text so they may be understood when rendered to speech.

In the following posts, insha Allah, we will go through the main guidelines of different versions of the WCAG.

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