Technique F39:Failure of Success Criterion 1.1.1 due to providing a text alternative that is not null (e.g., alt="spacer" or alt="image") for images that should be ignored by assistive technology

Applicability

Applies to HTML and XHTML.

This technique relates to 1.1.1: Non-text Content (Failure).

Description

This technique describes a failure condition for images that should be ignored by assistive technologies. A text alternative for an image should convey the meaning of the image. When an image is used for decoration, spacing or other purpose that is not part of the meaningful content in the page then the image has no meaning and should be ignored by assistive technologies.

Providing a null text alternative (i.e., alt="" ) will allow assistive technology to ignore the image and avoid a failure of this Success Criterion.

Examples

Example 1: Decorative images that have no alt attribute

An image is used to create a blank space between content, where the spacing itself is not meaningful to the content. The image has an alt text value of "spacer". This image fails the Success Criterion because the text alternative does not serve an equivalent purpose. The image is meant to be ignored but its alternative text "spacer" is announced by screen readers and displayed in some alternate color schemes. 

<div>Tree type: <img src="spacer.gif" width="100" height="1" alt="spacer"/>Cedrus deodara</div>

Tests

Procedure

  1. Identify any img elements that are used for decoration, spacing or other purpose that is not part of the meaningful content in the page
  2. Check that the alt attribute for these elements is null.

Expected Results

  • If step #2 is false, this failure condition applies and the content fails the Success Criterion.