Accessibility Standards

The W3C has crafted a number of accessibility standards, as introduced in the following video Introduction to Web Accessibility and W3C Standards created by the Web Accessibility Initiative :

The specific W3C standards covering web accessibility are:

Web Content Accessibility Guidelines (WCAG)

The WACG is built around four principles for content delivered through the web. It should be ¹:

1. Perceivable - Information and user interface components must be presentable to users in ways they can perceive. This means that users must be able to perceive the information being presented (it can’t be invisible to all of their senses).

2. Operable - User interface components and navigation must be operable. This means that users must be able to operate the interface (the interface cannot require interaction that a user cannot perform)

3. Understandable - Information and the operation of user interface must be understandable. This means that users must be able to understand the information as well as the operation of the user interface (the content or operation cannot be beyond their understanding)

4. Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. This means that users must be able to access the content as technologies advance (as technologies and user agents evolve, the content should remain accessible)

A discussion of the WCAG standards and the standards themselves can be found on the W3C WCAG page .

Authoring Tool Accessibility Guidelines (ATAG)

These guidelines apply to software tools made to help people author web content (i.e. wikis, content management systems, and web publishing tools). Increasingly, these are web apps that people use to author websites and other web apps. A discussion of the WCAG standards and the standards themselves can be found on the W3C ATAG page .

User Agent Accessibility Guidelines (UAAG)

These guidelines apply to user agents - software that consumes and displays information from the web. The best-known of these are web browsers and media players. A discussion of the WCAG standards and the standards themselves can be found on the W3C ATAG page .