Accessibility WCAG 2.0 Validation Rules

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Accessibility Home | Downloads | Rules for Ruleset 2.0 | Evaluation Library API 2.0 | Ruleset Format 2.0 | Issue Tracker


Goals for Ruleset Version 1.0

Ideas from Nick Hoyt

Filtering Features

  • Provide a way to filter out non-high priority rules
  • Provide a way to filter rule categories
  • Provide a way for users to filter by WCAG Success Criteria Level
    • A only
    • A and AA only
    • A, AA and AAA rules
  • Provide a way to filter result types
    • Show/Hide evaluation results of elements that are hidden
    • Show/Hide evaluation results of elements that pass a rule
    • Show/Hide evaluation results of elements that require element level manual check
    • Show/Hide evaluation results of elements that require page level manual check


  • Estimate about 100-110 rules in ruleset 1.0 (currently 58 rules)
  • At least one rule for each A and AA success criteria of WCAG 2.0
  • Each rule is assigned to a rule categories
  • Map each rule to WGAG 2.0 Success Criteria (primary and related)
  • Include the concepts of page- and element-based manual checks
  • Rule priority (independent of SC level): with only a handful of rules designated as highest priority.
  • ARIA Validation
    • role values
    • aria-properties and states
    • required children
    • required properties and states
  • Heading and Landmark rules
    • Rules when landmarks are not present
    • Rules when all content is in landmarks
    • What happens when there are some landmarks
  • Event handlers
    • Widget have event handlers
    • Mouse events are associated with interactive elements or ARIA widgets
  • Live Region Rules


  • Page-based manual checks are generally considered more important
  • Collection of rule sets supports transition to ARIA in a graduated fashion (Transitional and Strict)

ARIA transitional

  • ARIA landmark rules are recommended

ARIA strict

  • ARIA landmark rules are required

ARIA Organizational

  • require ARIA banner landmark
  • require ARIA navigation landmark
  • require ARIA contentinfo or complementary landmark

Links to OpenAjax Rules Grouped By WCAG 2.0 Principles




Data Tables


Forms Controls



Layout and Order



Previous WCAG 2.0 Rule References

Rule Information and Abbreviations

The accessibility validation rules enumerated in this document directly support WCAG 2.0, some with reference to the Document Object Model (DOM) and some with reference to the WAI-ARIA specification and WAI-ARIA best practices. Rules are divided according to the four principles of WCAG 2.0:

  1. Perceivable - Information and user interface components must be presentable to users in ways they can perceive
  2. Operable - User interface components and navigation must be operable
  3. Understandable - Information and the operation of user interface must be understandable
  4. Robust - Content must be robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies

Within each section representing a WCAG 2.0 principle is a table that contains:

  1. the guideline number, linked to that guideline in WCAG 2.0
  2. the success criterion
  3. the list of validation rules that apply to that criterion along with a suggested rule id for each rule
  4. a suggested violation level for each rule
  5. relevant techniques for implementing the success criterion or passing the given rules

For more information about the structure of WCAG 2.0 and an explanation of principles, guidelines, success criteria, and techniques, see WCAG 2.0 Layers of Guidance. Also, note that this document currently restricts itself to A and AA compliance for WCAG 2.0. Future work may include validation rules for AAA-level success criteria.

Although this document enumerates rules that directly support WCAG 2.0, there is no reason that the rule logic for evaluating each rule could not be reused in testing the items in other checklists. Indeed, one of the chief aims of this task force is to produce reusable rule objects that are readily-consumable and to help tool vendors avoid duplicating rule logic.

Rule Result Severity Levels

Only one of the following violation levels may be returned by a rule result n the document:

Pass (P)
requirement was met
Violation (V)
Indicates a direct violation of a success criterion or undermines a technique for implementing a success criterion
Warning (W)
Indicates direct violation of or non-conformance to a best practice
Manual Check (MC)
A condition for a potential violation has been met
A manual test is required to determine if success criterion have been met
Not Applicable (N/A)
The rule had no applicable elements on the page
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