It refers to the ability to access the Web and its contents by all people regardless of the disability (physical, intellectual or technical) that they present or those that derive from the context of use (technological or environmental). This quality is intimately related to usability.

When websites are designed with accessibility in mind, all users can access content in equal conditions. For example, when a site has a semantically correct XHTML code, an alternative equivalent text is provided to the images and the links are given a meaningful name, this allows blind users to use screen readers or Braille lines to access the contents . When videos have subtitles, users with hearing difficulties can fully understand them. If the contents are written in simple language and illustrated with diagrams and animations, users with dyslexia or learning problems are better able to understand them.

If the size of the text is large enough, users with visual problems can read it without difficulty. Similarly, the size of the buttons or the appropriate active areas can make it easier for users who can not control the mouse accurately. If you avoid the actions that depend on a specific device (press a key, click with the mouse) the user can choose the device that suits him best.

Limitations

The limitations in the accessibility of the websites can be:

– Visual: In its different degrees, from low vision to total blindness, in addition to problems to distinguish colors (Daltonism).
– Motrs: Difficulty or the impossibility of using the hands, including tremors, muscle slowness, etc., due to diseases such as Parkinson’s, muscular dystrophy, cerebral palsy, amputations …
– Auditory: Deafness or hearing deficiencies.
– Cognitive: Learning difficulties (dyslexia, dyscalculia, etc.) or cognitive disabilities that affect memory, attention, logical abilities, etc.

Web accessibility guidelines

The highest body within the Internet hierarchy that is responsible for promoting accessibility is the World Wide Web Consortium (W3C), especially its Web Accessibility Initiative (WAI) working group. In 1999, WAI published version 1.0 of its Web accessibility guidelines. With the passage of time they have become an internationally accepted reference. In December 2008, WCAG 2.0 was approved as an official recommendation.

These guidelines are divided into three blocks:

– Guidelines for Web Content Accessibility (WCAG) They are addressed to webmasters and indicate how to make the contents of the website accessible.

-Accessibility Guidelines for Authoring Tools (ATAG) They are aimed at software developers who use webmasters, so that these programs facilitate the creation of accessible sites

-Accessibility Guidelines for User Agents (UAAG) They are aimed at the developers of User Agents (browsers and similar), so that these programs provide all users with access to Web sites.