The included objects are provided with an appropriate fallback alternative.
Some digital books contain particular objects such as interactive javascript elements (form, map, etc. ) that may not be available in certain contexts. An alternative allows you to access their content. To prevent these elements from disappearing or displaying incorrectly, it is necessary to provide fallback content that conveys the information to the reader.
Objectives
Provide information access for users whose reading device does not support the inclusion of objects or technologies used in included objects.
Improve accessibility of content to readers with disabilities.
Implementation
Fournir des contenus de substitution pour les éléments particuliers (incluant des interactions des formulaires ou faisant appel à des ressources externes par exemple) afin qu’ils puissent être restitués aux lecteur en remplacement dans le cas où le dispositif de lecture ne pourrait pas les afficher.
Pour les fichiers EPUB, les contenus de substitution doivent être liés dans le spine ou dans le contenu des éléments spécifiques auxquels ils correspondent.
Control
Make sure the digital book remains readable and usable on an old device or by disabling javascript support
Verify that content using object or canvas tags is not essential for understanding, or is provided with a text alternative