WCAG 2: What they are, what they are meant to be

On December 11th, 2008, after 5 years of working, the W3C WAI released the WCAG 2.0 . They are an evolution of the WCAG 1.0, released on May 5th, 1999, that became a little bit obsolete due to technological advances. Despite this obsolescence, many laws still standed on these guidelines, so a new version was needed.

WCAG 2 follows the spirit of trying to bring a most accessible Web, but with some changes with the previous ones.

How are ‘WCAG 2’ organized?

WCAG 2 are organized by 4 layers: principles, guidelines, success criteria and techniques to accomplish them.

They provide the basis for Web accessibility: the website must be perceivable, operable, understandable, and robust.
There are 12 guidelines under the principles, similar to that on the WCAG 1, but with no levels of conformance
Success Criteria
Each guideline has a testable success criteria. Here they are the 3 levels of conformance, equal to that on WCAG 1: A (lowest), AA, and AAA (highest).
Each guideline and success criteria has itw own informative techniques. There are 2 categories plus sufficient techniques and the advisory ones that address. The WAI had also documented some common failures, so we can learn how to avoid them.

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