Technique G143:Providing a text alternative that describes the purpose of the CAPTCHA

Applicability

Applies to all technologies.

This technique relates to 1.1.1: Non-text Content (Sufficient, together with G144: Ensuring that the Web Page contains another CAPTCHA serving the same purpose using a different modality).

Description

The purpose of this technique is to provide information via the text alternative that identifies the non-text content as a CAPTCHA. Such tests often involve asking the user to type in text that is presented in an obscured image or audio file. From the text alternative, the user can tell that the CAPTCHA requires completing a task and what type of task it is.

When an alternate version of a CAPTCHA is available, the text alternative should include instructions about how to find the alternate version.

Examples

  • A CAPTCHA test asks the user to type in text that is displayed in an obscured image. The text alternative is "Type the word in the image".
  • A CAPTCHA test asks the user to type in text that is played in an audio file. The text alternative is "Type the letters spoken in the audio".

Tests

Procedure

  1. Remove, hide, or mask the CAPTCHA.
  2. Replace it with the text alternative.
  3. Check that the text alternative describes the purpose of the CAPTCHA.

Expected Results

  • Check #3 is true.