How does it work?

To make Web content accessible, they have developed so-called Accessibility Guidelines Web Content (WCAG), whose main function is to guide the design of web pages towards an accessible design, thereby reducing barriers to information.

WCAG, version 2.0, consists of four principles distributed in 12 patterns that provide design solutions and used as examples common situations in which the layout of a page can produce problems of access to information. The guidelines also contain a number of criteria in accordance that help detect possible errors. For each criterion under there are 3 levels of conformity (A, AA and AAA).

WCAG 2.0 supports any technology to support accessibility and therefore can be applied to multimedia content, JavaScript, PDF, etc.

When a website is required to be accessible, it must also be included as part of the website, a "Declaration of accessibility compliance" should include the date, title, version, and URI WCAG, the level of compliance a description of the pages that affects the declaration and a list of technologies on which depends the content.

The 4 principles that WCAG 2.0 is based are:

Noticeable

The information and components of the user interface should be presented to users in the way they can perceive.

Operable

The information and components of the user interface should be presented to the user how to operate them.

Comprehensible

The information and management of the user interface must be understandable.

Robust

Content must be robust enough to rely on its interpretation by a wide variety of user agents, including assistive technologies.

Based on these principles and standards compliance levels are established:

• Conformance Level "A": all the criteria are met under A.
• Conformance Level "AA" AA all compliance criteria are met.
• Conformance Level "AAA": all AAA conformance criteria are satisfied.