Web Accessibility

About WCAG 2.0

What is WCAG 2.0?

WCAG 2.0 is a set of guidelines from the World Wide Web Consortium, the organisation that creates standards for web technologies and languages such as HTML and CSS. The guidelines are a range of recommendations for making web content accessible to people with a range of disabilities, including visual, auditory, physical, speech, cognitive, language, learning, and neurological disabilities. These people may be using a range of assistive technologies. This particular version of WCAG is designed to be independent of technology and any particular disability, so you do not need to worry about how someone may be using your web resources, although it is useful to know why you should. The mean of doing this with particular technologies is set out in the WCAG techniques.

WCAG 2.0 is divided into four principles and 12 guidelines:

Principle 1: Perceivable

  • Provide text alternatives for non-text content.
  • Provide captions and other alternatives for multimedia.
  • Create content that can be presented in different ways, including by assistive technologies, without losing meaning.
  • Make it easier for users to see and hear content.

Principle 2: Operable

  • Make all functionality available from a keyboard.
  • Give users enough time to read and use content.
  • Do not use content that causes seizures.
  • Help users navigate and find content.

Principle 3:Understandable

  • Make text readable and understandable.
  • Make content appear and operate in predictable ways.
  • Help users avoid and correct mistakes.

Principle 4: Robust

  • Maximize compatibility with current and future user tools.

WCAG 2.0 contains what are called layers of guidance. Each of the 12 guidelines has several testable success criteria, which are classified according to a conformance or priority level. These levels, Single A (A) (lowest), Double A (AA), and Triple A (AAA) (highest), relate to the impact on the user if they are not met. Each criterion contains many techniques, relating to different technologies, describing how to meet them. The techniques are sorted into those that are sufficient to meet the criteria, and those that are advisory. Advisory techniques enhance accessibility, but are not testable.