The Web Content Accessibility Guidelines 2.0 (WCAG 2.0) are a set of standards defines by the W3C that define how to make Web content more accessible to people with disabilities. All of the accessibility work of the W3C is housed under the Web Accessibility Initiative (WAI). WCAG 2.0 defines four principles which provide the foundation for Web accessibility.
- Perceivable – Information and user interface components must be presented to users in ways that they can perceive, regardless of the user’s functional impairment
- Operable – user interface components and navigation must be operable, regardless of the assistive technology used to interact with the interface
- Understandable – information and the operation of the user interface must be predictable and understandable to the user
- Robust – content must be robust enough to be able to be transformed and interpreted by a wide variety of user agents, like assistive technologies
In addition to the principles there are a set of guidelines which expand the principles by delineating a set of goals content creators should have in making their content accessible. The guidelines are not themselves testable, but rather a set of “Success Criteria” are given that are testable. The Success Criteria have three different conformance levels – A, AA, and AAA, with AAA being the most accessible. Additionally there are “Sufficient and Advisory Techniques” that demonstrate coding techniques.
Further, there are a number of techniques and guidelines in addition to WCAG 2.0, such as how to make rich internet applications accessible (ARIA), how user agents like browsers should be made accessible, and more. All of this information is available from the Web Accessibility Initiative.
The Web Content Accessibility Guidelines 2.0 (WCAG 2.0) is a rich and complex standard. Sometimes it can be difficult to understand all aspects of WCAG 2.0. This guide is largely based on the work surrounding WCAG 2.0, however, it presents it in a more approachable manner for those newer to Web accessibility. Additionally, some of the additional techniques in the ARIA suite are presented here too.