Rulesets

The Functional Accessibility Evaluator and AInspector for Firefox use the OpenA11y Evaluation Library and Rulesets. The OpenA11y Evaluation Library rules and rulesets and are based on the Level A and AA success criteria defined in W3C Web Content Guidelines 2.0 using best practices for implementing accessibility defined in the W3C ARIA Authoring Practices and the W3C ARIA in HTML specifications.

HTML4 Legacy Techniques

WCAG 2.0 Level A and AA requirements primarily using HTML4 techniques, but allows HTML5 and ARIA accessibility techniques.

Evaluation of W3C Web Content Accessibility Guidelines 2.0 Level A and AA conformance using HTML4 accessibility techniques, but allows for the use of HTML5 and ARIA techniques. ARIA landmarks are NOT required, but if used must follow landmark and sectioning element requirements as outlined in HTML5 and ARIA. The ruleset does NOT require the use of ARIA widget roles for identifying and describing interactive elements (e.g. popup menus, grids, trees, etc...) that cannot be not described by the native semantics of HTML4 and HTML5 form control and link elements. This means the developer will need to do more manual checking and have a high level understanding of assistive technology to describe widgets typically using offscreen text and/or small images (e.g. with ALT text) to define and manage the roles, properties and states of interactive elements.

  • Version: 1.2.0
  • Total Rules: 126
  • Required Rules: 81
  • Recommended Rules: 45

HTML5 and ARIA Techniques

WCAG 2.0 Level A and AA requirements using ARIA and HTML5 accessibility features.

Evaluation of W3C Web Content Accessibility Guidelines 2.0 Level A and AA conformance using HTML5 and ARIA accessibility techniques. ARIA Landmarks are required for the identification and labeling of the sections of content on a web page. The ruleset requires the use of ARIA widget roles for identifying and describing interactive elements (e.g. popup menus, grids, trees, etc...) that cannot be not described by the native semantics of HTML5 form control and links elements.

  • Version: 1.2.0
  • Total Rules: 136
  • Required Rules: 109
  • Recommended Rules: 27

Ruleset Comparison

Landmarks

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Landmark 1 main landmark: at least one A 2.4.1 - Required
Landmark 10 navigation landmark: restrictions A 1.3.1 Recommended Required
Landmark 11 main landmark: must be top-level A 1.3.1 Recommended Required
Landmark 12 contentinfo landmark: must be top-level A 1.3.1 Recommended Required
Landmark 13 contentinfo landmark: restrictions A 1.3.1 Recommended Required
Landmark 14 search landmark: restrictions A 1.3.1 Recommended Required
Landmark 15 form landmark: restrictions A 1.3.1 Recommended Required
Landmark 16 region landmark must have accessible name A 1.3.1 Recommended Required
Landmark 17 Landmarks must be uniquely identifiable A 1.3.1 Recommended Required
Landmark 18 Landmarks must identify content regions A 1.3.1 Required Required
Landmark 19 complementary landmark: must be top level A 1.3.1 Recommended Required
Landmark 2 All content must be contained in landmarks A 1.3.1 - Required
Landmark 3 navigation landmark: at least one A 2.4.1 - Required
Landmark 4 banner landmark: identifies branding content A 2.4.1 - Required
Landmark 5 banner landmark: no more than one A 2.4.1 Recommended Required
Landmark 6 contentinfo landmark: identifies admin content A 2.4.1 - Required
Landmark 7 contentinfo landmark: no more than one A 2.4.1 Recommended Required
Landmark 8 banner landmark: must be top-level A 1.3.1 Recommended Required
Landmark 9 banner landmark: restrictions A 1.3.1 Recommended Required

Headings

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Heading 1 Page must have h1 element A 2.4.1 Recommended Recommended
Heading 2 h1 must be in main or banner landmark AA 2.4.6 Recommended Recommended
Heading 3 Sibling headings must be unique AA 2.4.6 Recommended Recommended
Heading 5 Headings must be properly nested A 1.3.1 Required Required
Heading 6 Headings must have text content A 1.3.1 Recommended Recommended
Heading 7 First landmark heading h2 A 1.3.1 - Recommended
Heading 8 Headings nested in landmarks A 1.3.1 - Required
Role 10 Overriding h1-h6 role semantics. (Deprecated) A 1.3.1 Recommended Recommended

Styles/Content

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Color 1 Text must exceed CCR threshold AA 1.4.3 Required Required
Color 2 Use of color A 1.4.1 Required Required
Frame 1 frame must have accessible name A 2.4.1 Required Required
Frame 2 iframe must have accessible name A 2.4.1 Required Required
HTML 1 Replace b and i elements A 4.1.1 - -
HTML 2 Replace marquee elements A 2.3.1 Required Required
Language 1 Page must use language code A 3.1.1 Required Required
Language 2 Identify language changes AA 3.1.2 Required Required
Layout 2 Do not nest layout tables A 1.3.2 Recommended Recommended
Layout 3 Verify aria-flowto supports reading order A 1.3.2 Required Required
List 1 Use semantic markup for lists A 1.3.1 Required Required
List 2 Provide list labels when appropriate AA 2.4.6 Recommended Recommended
Order 1 Reading order: CSS positioning A 1.3.2 Required Required
Resize 1 Resize text content AA 1.4.4 Required Required
Role 1 main element role semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 11 li element group item semantics. (Deprecated) A 4.1.2 Recommended Recommended
Role 2 body element role semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 3 ol and ul role grouping semantics. (Deprecated) A 4.1.2 Recommended Recommended
Role 4 article element role semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 5 section element role semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 6 Do not override nav element semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 7 aside element role semantics. (Deprecated) A 1.3.1 Recommended Recommended
Role 8 Do not override header element role. (Deprecated) A 1.3.1 Recommended Recommended
Role 9 Do not override footer element role. (Deprecated) A 1.3.1 Recommended Recommended
Sensory 1 Not only shape, size and location A 1.3.3 Required Required

Images

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Image 1 Images must have alt text A 1.1.1 Required Required
Image 2 Alt text must summarize purpose A 1.1.1 Required Required
Image 3 Alt text must not include filename A 1.1.1 Required Required
Image 4 (English) Alt text no more than 100 characters A 1.1.1 Recommended Recommended
Image 5 Verify image is decorative A 1.1.1 Required Required
Image 6 Long description for complex images A 1.1.1 Required Required
Image 7 Use MathML for mathematical expressions A 1.1.1 Required Required
Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Focus 3 Target focus must be in content window A 3.2.1 Required Required
Link 1 Link text must describe the link target A 2.4.4 Required Required
Link 2 Link text must be unique A 2.4.4 Recommended Recommended
Role 12 a[href] element role semantics. (Deprecated) A 4.1.2 Recommended Recommended

Tables

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Layout 1 Layout tables must have meaningful sequence A 1.3.2 Required Required
Table 1 Data cells must have row/column headers A 1.3.1 Required Required
Table 2 Data tables must have name AA 2.4.6 Recommended Recommended
Table 3 Data tables must have description A 1.3.1 Recommended Recommended
Table 4 Data tables must have unique names A 1.3.1 Required Required
Table 5 Identify table markup as data or layout A 1.3.1 Recommended Required
Table 6 Header cells must be th elements A 1.3.1 Recommended Required
Table 7 Data cells must use headers attribute A 1.3.1 Required Required
Table 8 Name must be different than description A 1.3.1 - Required

Forms

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Control 1 Form controls must have labels A 3.3.2 Required Required
Control 10 Labels must be unique AA 2.4.6 Required Required
Control 11 Submit and reset button labels must be unique AA 2.4.6 Required Required
Control 2 Image button must have alt. content A 3.3.2 Required Required
Control 3 Radio buttons must have grouping label A 3.3.2 Required Required
Control 4 buttons must have content A 3.3.2 Required Required
Control 5 id must be unique A 4.1.1 Required Required
Control 6 label must reference control A 3.3.2 Required Required
Control 7 label must have content A 3.3.2 Required Required
Control 8 fieldset must have one legend A 3.3.2 Required Required
Control 9 Verify title is the label. A 3.3.2 Required Required
Error 1 Information on invalid values A 3.3.1 Required Required
Error 2 Required form controls AA 3.3.3 Required Required
Error 4 Error correction suggestions AA 3.3.3 Required Required
Error 5 Prevent errors AA 3.3.4 Required Required
Focus 4 select must not change context A 3.2.2 Required Required
Focus 5 Forms submitted using buttons A 3.2.2 Required Required
Focus 6 checkbox/radio buttons changing context. A 3.2.2 - -
Role 13 select element role semantics. (Deprecated) A 4.1.2 Recommended Recommended
Role 14 textarea element role semantics. (Deprecated) A 4.1.2 Recommended Recommended

Widgets/Scripts

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Error 3 Required widgets AA 3.3.3 - Required
HTML 3 Role is not allowed A 4.1.2 Required Required
Widget 1 Widgets must have label A 4.1.2 Required Required
Widget 10 Value in range A 4.1.2 Required Required
Widget 11 Elements with event handlers must have roles A 4.1.2 Required Required
Widget 12 Widget labels must be descriptive AA 2.4.6 Required Required
Widget 13 Role does not support accessible name. A 4.1.2 Recommended Required
Widget 14 Verify appropriate use of live region A 4.1.2 Required Required
Widget 15 Remove deprecated ARIA attributes. A 4.1.1 Recommended Recommended
Widget 16 Closed shadow DOM requires manual check. A 2.1.1 Required Required
Widget 2 onClick event handlers must have role A 4.1.2 - Required
Widget 3 role must be valid A 4.1.2 Required Required
Widget 4 ARIA values must be valid A 4.1.2 Required Required
Widget 5 Attributes that start with aria- must be defined. A 4.1.2 Required Required
Widget 6 Widgets must have properties A 4.1.2 Required Required
Widget 7 Widgets must have owned elements A 4.1.2 Required Required
Widget 8 Role must have parent A 4.1.2 Required Required
Widget 9 Only one owner A 4.1.2 Required Required

Audio/Video

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Audio 1 audio must have alternative A 1.2.1 Required Required
Audio 2 object for audio must have alternative A 1.2.1 Required Required
Audio 3 embed for audio must have alternative A 1.2.1 Required Required
Audio 4 Pause, stop or mute audio A 1.4.2 Required Required
Video 1 video for video only must have alternative A 1.2.1 Required Required
Video 2 object for video only must have alternative A 1.2.1 Required Required
Video 3 embed for video only must have alternative A 1.2.1 Required Required
Video 4 video must have caption A 1.2.2 Required Required
Video 5 object for video must have captions A 1.2.2 Required Required
Video 6 embed for video must have captions A 1.2.2 Required Required
Video 7 video element must have audio description. A 1.2.3 Required Required
Video 8 object for video must have audio description. A 1.2.3 Required Required
Video 9 embed for video must have audio description A 1.2.3 Required Required

Keyboard

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Bypass 1 Skip to main content link A 2.4.1 Recommended Recommended
Focus 1 Focus order must be meaningful A 2.4.3 Required Required
Focus 2 Focus must be visible AA 2.4.7 Required Required
Keyboard 1 Widget roles require keyboard support A 2.1.1 Required Required
Keyboard 2 Interactive functionality must be keyboard operable A 2.1.1 Required Required
Keyboard 3 No keyboard trap A 2.1.2 Required Required

Timing

Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Timing 1 Control time limits A 2.2.1 Required Required
Timing 2 Control moving, blinking or auto-updating content A 2.2.2 Required Required
Timing 3 Flashing limits A 2.3.1 Required Required
Rule ID Summary Level SC HTML4 Legacy Techniques HTML5 and ARIA Techniques
Navigation 1 At least two ways of finding content AA 2.4.5 Recommended Required
Navigation 2 Consistent ordering of landmarks AA 3.2.3 Recommended Required
Navigation 3 Consistent ordering of h1 and h2 labels AA 3.2.3 Required Required
Navigation 4 Consistent labeling of landmarks AA 3.2.4 Recommended Required
Navigation 5 Consistent h1 and h2 page section labels AA 3.2.4 Required Required
Title 1 title must identify website and page A 2.4.2 Required Required
Title 2 h1 must match part of the title A 2.4.2 - -