It refers to the ability to access the Web and its contents by all persons regardless of the disability (physical, intellectual or technical) that they present or from the context of use (technological or environmental). This quality is closely related to usability.
When web sites are designed with accessibility in mind, all users can access content on an equal basis. For example, when a site has a semantically correct XHTML code, alternative equivalent text is provided to the images and links are given a meaningful name, this allows blind users to use screen readers or Braille lines to access content . When videos have closed captions, users with hearing difficulties will be able to 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 text size is large enough, visually impaired users can read it easily. Similarly, the size of the buttons or the active areas appropriate can facilitate their use to users who can not control the mouse accurately. If you avoid actions that depend on a specific device (click a key, click with the mouse) the user can choose the device that suits him.
Limitations
The limitations in the accessibility of the Web sites can be:
– Visual: In its different degrees, from the low vision to the total blindness, besides problems to distinguish colors (Daltonismo).
– Motrices: Difficulty or inability to use the hands, including tremors, muscle slowness, etc., due to diseases such as Parkinson’s, muscular dystrophy, cerebral palsy, amputations …
– Hearing: Deafness or hearing impairment.
– Cognitive: Learning difficulties (dyslexia, dyscalculia, etc) or cognitive disabilities that affect memory, attention, logical skills, etc.
Web accessibility guidelines
The World Wide Web Consortium (W3C), in particular its Web Accessibility Initiative (WAI) working group, is the highest body within the Internet hierarchy that promotes accessibility. In 1999 the WAI published version 1.0 of its Web accessibility guidelines. With the passage of time they have become an internationally accepted benchmark. In December 2008 the WCAG 2.0 were approved as an official recommendation.
These guidelines are divided into three blocks:
– Web Content Accessibility Guidelines (WCAG) Are directed to webmasters and indicate how to make the contents of the website accessible.
– Author Tool Accessibility (ATAG) courses are intended for software developers using webmasters, so that these programs facilitate the creation of accessible sites
– User Agent Accessibility Guidelines (UAAG) These are intended for developers of User Agents (browsers and the like), so that these programs provide all users with access to Web sites.