Glossary

Accessibility (a11y)

Accessibility (a11y) is building the web so that people with disabilities can use it fully. Around 15% of the population has some form of disability. In many countries, web accessibility is a legal requirement.

Main categories

Visual — blindness, low vision. Tool: screen reader (NVDA, VoiceOver)
Auditory — deafness. Captions and transcripts needed
Motor — keyboard-only control. All functionality must be reachable without a mouse
Cognitive — plain language, predictable navigation

Practice

Semantic HTML: <button> instead of <div onclick>
Alt text for images
Text contrast: minimum 4.5:1 (WCAG AA)
aria-label, role for custom components
Visible keyboard focus (:focus-visible)