EPUB 3 Accessibility Guidelines

In the same way that XHTML tables provide markup structure that can be navigated by readers using assistive technologies, so too must Media Overlay documents provide equivalent skippability and escapability functionality through markup to facilitate playback.

This structure can be layered into an overlay using seq elements to represent the corresponding rows and cells in the markup. The typical process for converting table markup to overlay markup follows:

• A single seq element encloses the entire table, and includes an epub:type attribute specifying the property table.
• Each row in the table is represented using a seq element with an epub:type attribute specifying the property table-row.
• Complex table cells — those that contain two or more synchronization points — are identified using seq elements with an epub:type attribute specifying the property table-cell. If the cell contains a complex structure like a nested table or list, that structure must be marked up as appropriate to ensure escapability and skippability from it.
• Simple table cells containing only a single synchronization point can be represented using par elements with an epub:type attribute specifying the property table-cell.