WCAG (Web Content Accessibility Guidelines)
This article is a definition of terms for WCAG – including exam questions, core components, and tags.
In a Nutshell
WCAG defines testable success criteria for accessibility along four principles:
- perceivable
- operable
- understandable
- robust
The typical target standard in projects is WCAG AA.
Compact Technical Description
WCAG (from W3C) has conformance levels:
- A (Minimum)
- AA (Practice standard)
- AAA (Extended, not realistic everywhere)
The four principles are called POUR as an acronym.
Typical success criteria (examples):
- Contrast (AA usually 4.5:1 for body text)
- Keyboard operability
- Focus visible
- Clear labels/error messages
Implementation:
- Semantic HTML before ARIA
- Logical order
- Focus management
- Understandable error handling
Evidence: Automated scans + manual checks + Screen reader/keyboard tests.
Exam-Relevant Key Points
- Explain POUR
- Distinguish levels A/AA/AAA
- Name contrast values
- Keyboard path + focus visible
- Tests: Scanner + manual + Assistive technology
- Documentation: Checklist, test protocols, style guide
- Relationship to EN 301 549 (EU)
Core Components
- Principles + success criteria
- Target level (AA) + scope
- Semantics/structure
- Keyboard operability
- Contrast + perceivability
- Labels/name-role-value
- Error tolerance/error messages
- Media alternatives
- Robust technology + ARIA correct
- QA process + protocols
Practical Example (Form)
- Visible labels + programmatic association
- Keyboard order linear, focus visible
- Error list links fields, error messages near fields
- Contrast 4.5:1 for text
- A11y checklist + test protocol in repo
Typical Exam Questions (with Short Answer)
- What does POUR mean? Perceivable, Operable, Understandable, Robust.
- AA contrast for body text? At least 4.5:1.
- How do you test efficiently? Automated + manual + keyboard/screen reader.