Definition
Alternative text is provided for visual content (e.g., via the [HTML] alt attribute).
Examples
Example 1 — EPUB 3
<meta property="schema:accessibilityFeature">
alternativeText
</meta>
Example 2 — EPUB 2
<meta name="schema:accessibilityFeature"
content="alternativeText"/>
Example 3 — Audiobooks
"accessibilityFeature": ["alternativeText"]
Explanation
The alternativeText
value is used to indicate that all images and other non-text content (e.g., audio and
video) that is relevant to understanding a publication includes a text alternative.
Alternative text provided using the HTML alt
attribute.
<img src="rabbit.jpg" alt="Bugs Bunny" />
Presentational images (i.e., that are only used for purely display or ornamentation purposes) are excluded from the requirement for alternative text, so not every image or instance of non-text content will have a text alternative when this property is set.
A presentational image.
<img src="spacer.jpg" alt="" role="presentation" />
See the Image Descriptions knowledge base page for more information.
Related Links
- Schema.org — accessibilityFeature
- Schema.org Accessibility Vocabulary — alternativeText