WCAG and what the levels mean.
WHAT WCAG IS
The Web Content Accessibility Guidelines. The internationally recognised standard.
Most legal requirements reference it.
THE LEVELS
- Level A: the minimum. Failing these makes content unusable for some people.
- Level AA: the usual target, and what most regulations specify.
- Level AAA: stricter, and not achievable or appropriate for all content.
WHAT TO AIM FOR
Level AA. That is the practical standard.
THE FOUR PRINCIPLES
- Perceivable: people can perceive the content, through sight, hearing or touch
- Operable: people can navigate and interact
- Understandable: content and behaviour make sense
- Robust: it works with assistive technology
THOSE FOUR
Useful as a way of thinking rather than a checklist.
If content is invisible to a screen reader, it is not perceivable. If a control cannot be reached by keyboard, it is not operable.
WHAT THE GUIDELINES ACTUALLY CONTAIN
Specific testable criteria: contrast ratios, keyboard requirements, text alternatives.
WHERE TO START
Not by reading the standard. By fixing the common failures, which are covered in the following articles.
