CodeParkWCAG (Web Content Accessibility Guidelines) is the W3C standard for web accessibility. Versions are 2.0 (2008), 2.1 (2018) and 2.2 (2023). Each version adds rules and keeps the old ones, except that 2.2 removed the old 4.1.1 Parsing rule.
WCAG is built on four principles, called POUR:
- Perceivable: users can sense the content. Examples: alt text for images, captions for video, enough colour contrast.
- Operable: users can work every control. Examples: everything works with a keyboard, no time traps, nothing flashes dangerously.
- Understandable: content and behaviour make sense. Examples: clear labels, helpful error messages, predictable navigation.
- Robust: content works with many browsers and assistive technologies. Example: correct roles and names, so a screen reader can tell what a control is.
Under the principles are testable success criteria. Each one has a level:
- A: the basic minimum. Missing it blocks some users completely.
- AA: the normal target. It includes A, plus rules like 4.5:1 text contrast.
- AAA: the strictest. W3C says not to require it for whole sites, because some content can't meet it.
Most laws and contracts ask for WCAG 2.1 AA or 2.2 AA. That is the usual team target.
- WCAG is the W3C accessibility standard, and the current version is 2.2.
- POUR stands for Perceivable, Operable, Understandable and Robust.
- Each success criterion is testable and has a level A, AA or AAA.
- AA includes all of A and is the usual legal and team target.
- AAA is not recommended as a requirement for a whole site.