Perceivable principle
This principle speaks to the need for web content to be made available to all the senses such as sight, hearing and/or touch. It involves:
- providing text and/or auditory alternatives for non-text content allowing it to be changed into other forms i.e. large print, Braille, speech, symbols or simpler language
- preserving information and relationships that are implied by visual or auditory formatting when the presentation format changes
- ensuring that the reading and navigation order are the same regardless of screen size, screen orientation (portrait/landscape), assistive technology, etc.
- making sure that the instructions do not rely on any auditory (beeping) or visual queues (shape, size, location e.g. click the square icon to continue) only
- making it easier for users to see and hear content including but not limited to:
- effective colour contrast
- responsive images and text
- mechanisms to stop, pause, mute and adjust volume
Applicable criterions
1.1.1 - Non-text content
1.2.1 - Audio-only and video-only (prerecorded)
1.2.2 - Captions (prerecorded)
1.2.3 - Audio description or media alternative (prerecorded)
1.2.4 - Captions (live)
1.2.5 - Audio description (prerecorded)
1.3.1 - Info and relationships
1.3.2 - Meaningful sequence
1.3.3 - Sensory characteristics
1.4.1 - Use of colour
1.4.2 - Audio control
1.4.3 - Contrast (minimum)
1.4.4 - Resize text
1.4.5 - Images of text
1.4.11 - Non-text contrast