The purpose of this success criterion is to ensure that users who cannot access non-textual content (such as graphics, charts, audio, and video) have access to the information contained in that content in textual form.
How to Meet
How to meet this requirement depends on the complexity of the information expressed. The requirements generally break down along the following lines:
- For image content whose information can be conveyed in a sentence or less, authors only need
to provide alternative text (e.g., in an
- If the image information is more complicated (e.g., for charts and graphs), authors need to provide both a brief alternative text and an extended description.
- For audio and video, a label is provided that gives the title or briefly describes the purpose (additional audio and video requirements, such as the need for transcripts or captions are covered under 1.2).
- For user controls (e.g., buttons and sliders), a text alternative is required that describes the function of the control. The text alternative typically is a label.
Note that this success criterion only applies to non-text content that expresses information the reader needs to understand. Images that are included purely for aesthetic reasons (e.g., to decorate the start of a new section) do not require text alternatives. As visual readers gain nothing from these images, there is no need for non-visual readers to be made aware of them.
There is also an exception to this success criterion when providing a text alternative would invalidate the purpose of the content. For example, if an author includes a test that requires audio rendering of the question (e.g., to test spelling).
The following knowledge base pages provide more information about how to address this success criterion for publishing content: