Perceivable.
People need to be able to perceive the content — see it, hear it, or otherwise access it. This is where alt text, captions, colour contrast, and resizable text live.
- Provide text alternatives for images
- Provide captions for video and transcripts for audio
- Use sufficient colour contrast
- Make content adaptable to different presentations without losing meaning
Operable.
People need to be able to navigate and use your site with whatever tools they have.
- Make all functionality available from a keyboard
- Give users enough time to complete tasks
- Don’t design content that causes seizures
- Provide clear navigation and way-finding
- Ensure touch targets are large enough (new in 2.2)
Understandable.
The content and interface need to make sense.
- Write in plain, readable language
- Make pages behave predictably
- Help users avoid and correct mistakes in forms
- Provide consistent help mechanisms (new in 2.2)
Robust.
The content needs to work across different browsers, devices, and assistive technologies.
- Use valid, semantic HTML
- Ensure compatibility with assistive technologies
- Don’t rely on non-standard code or techniques
