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Section 508 ICT Testing Baseline

18. CSS Content and Positioning

Accessibility Requirements

  • WCAG SC 1.1.1 Non-Text Content – All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for the situations listed below.
    • Decoration, Formatting, Invisible: If non-text content is pure decoration, is used only for visual formatting, or is not presented to users, then it is implemented in a way that it can be ignored by assistive technology.
  • WCAG SC 1.3.1 Info and Relationships – Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.
  • WCAG SC 1.3.2 Meaningful Sequence – When the sequence in which content is presented affects its meaning, a correct reading sequence can be programmatically determined.

Test Method Rationale

Meaningful information provided solely through CSS content may not be in the Document Object Model (DOM). Equivalent information must be available without CSS.

Limitations, Assumptions, or Exceptions

  • Only the CSS techniques identified as Failures in WCAG 2.0 Level A and Level AA are included in this test. There may be other CSS techniques that affect conformance.
  • Inline styling is included in this test.

18.1 Test Procedure for Meaningful Background Image

Baseline Test ID: 18.1-CSSMeaningfulImage

Identify Content

Meaningful background images rendered by CSS

Test Instructions

  1. Check that the meaningful CSS image provides an equivalent text alternative description: [SC 1.1.1]
    • ARIA role=”img” and non-empty aria-label value, and
    • The aria-label value provides the same information as the meaningful background image

Test Results

If any of the above checks fail, then Baseline Test 18.1-CSSMeaningfulImage fails.

18.2 Test Procedure for CSS Positioned Content

Baseline Test ID: 18.2-CSSPositionedContent

Identify Content

Content positioned with CSS position

Test Instructions

  1. Check that the reading order of the content (in context) is correct without the CSS position property. [SC 1.3.2]
  2. Check that the meaning of the content (in context) is preserved without the CSS position property. [SC 1.3.2]

Test Results

If any of the above checks fail, then Baseline Test 18.2-CSSPositionedContent fail.

Advisory: Tips for streamlined test processes

WCAG 2.0 Techniques

The following sufficient techniques and/or common failures were considered when developing this test procedure for this baseline requirement:

Contact the ICT Baseline Working Group

Related Projects

The Baseline Alignment for Web is being developed to aid in determining if a test process aligns with the ICT Baseline for Web.