Ensuring information is presentable to all senses.
The Perceivable principle is the sensory foundation of the web. It ensures that information isn't "invisible" to any user, regardless of how they interact with their device. By providing content through sight, sound, and touch, we ensure that every visitor can ingest information in the way that works best for them.
Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.
Primary Implementation: Using alt attributes for images and providing text-based labels for icons and buttons.
Provide alternatives for time-based media, including synchronized captions for video, audio descriptions for visual information, and full-text transcripts for podcasts.
Primary Implementation: Ensuring all video content has captions that are accurate and synchronized with the audio track.
Review Media Alternative StandardsCreate content that can be presented in different ways (for example simpler layout) without losing information or structure.
Primary Implementation: Using semantic HTML (headings, lists, landmarks) so that the structure is programmatically determinable by assistive technology.
Master Semantic Info & RelationshipsMake it easier for users to see and hear content including separating foreground from background.
Primary Implementation: Ensuring high color contrast ratios (at least 4.5:1 for standard text) and allowing users to resize text without breaking functionality.
Examine Contrast & Distinguishable StandardsPerceivability isn't just about screen readers. It's about the user with low vision who needs high contrast, the user in a loud environment who needs captions, and the user with situational disabilities. If your content relies on a single sense to be understood, it is not yet Perceivable.