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Techniques for WCAG 2.0

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G148: Not specifying background color, not specifying text color, and not using technology features that change those defaults

Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.

Applicability

Any technology where text and background color are specified separately and browsers can control default colors.

This technique relates to:

Description

The objective of this technique is to make sure that users can read text that is presented over a background. With this technique the author avoids having to do any contrast measures by simply not specifying the text color and not specifying the background. As a result the colors of both are completely determined by the user agent.

Some people who have vision disabilities set their user agent to override certain colors that they have trouble seeing. This technique will help avoid a situation where the user agent and web site conflict with each other over the foreground and/or background colors resulting in the same color for text and background, which would make it invisible for user who set their own colors in their browser or Assistive Technology.

Examples

Example 1

The author specifies neither text color nor background, and does not use CSS. As a result the user can set his browser defaults to provide the colors and contrasts that work well for them.

Resources

Resources are for information purposes only, no endorsement implied.

Tests

Procedure

  1. Look in all places that text color can be specified

  2. Check that text color is not specified

  3. Look in all areas that background color or image used as a background can be specified

  4. Check that no background color or image used as a background is specified

Expected Results

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.

This Web page is part of Techniques and Failures for Web Content Accessibility Guidelines 2.0 (see the latest version of this document). The entire document is also available as a single HTML file. See the The WCAG 2.0 Documents for an explanation of how this document fits in with other Web Content Accessibility Guidelines (WCAG) 2.0 documents. To send public comments, please follow the Instructions for Commenting on WCAG 2.0 Documents.

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