Techniques for WCAG 2.0

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F4: Failure of Success Criterion 2.2.2 due to using text-decoration:blink without a mechanism to stop it in less than five seconds

Applicability

Cascading Style Sheets.

This failure relates to:

User Agent and Assistive Technology Support Notes

See User Agent Support Notes for F4.

Description

CSS defines the blink value for the text-decoration property. When used, it causes any text in elements with this property to blink at a predetermined rate. This cannot be interrupted by the user, nor can it be disabled as a user agent preference. The blinking continues as long as the page is displayed. Therefore, content that uses text-decoration:blink fails the Success Criterion because blinking can continue for more than three seconds.

Examples

Failure Example 1

A product list page uses the text-decoration:blink style on an element to draw attention to sale prices. This fails the Success Criterion because users cannot control the blink.

Example Code:


<p>My Great Product <span style="text-decoration:blink">Sale! $44,995!</span></p>

Resources

Resources are for information purposes only, no endorsement implied.

Tests

Procedure

  1. Examine inline styles, internal stylesheets, and external stylesheets for the text-decoration property with a value of "blink".

  2. If the property is used, determine if the ID, class, or element identified by selectors on which this property is defined are used in the document.

Expected Results

Techniques are Informative

Techniques are informative—that means they are not required. The basis for determining conformance to WCAG 2.0 is the success criteria from the WCAG 2.0 standard—not the techniques. For important information about techniques, please see the Understanding Techniques for WCAG Success Criteria section of Understanding WCAG 2.0.