Accessibility tree

The accessibilty tree is a representation of a web document created by browsers that is optimized for navigation by assistive technology.

The accessibility tree is essentially a modified version of the HTML DOM. It includes additional information, such as accessible names and descriptions, and also omit some unnecessary information that is only useful for visual rendering.


Ace is an accessibility checking tool for EPUB publications developed by the DAISY Consortium.

Ace checks publications for common WCAG violations that can be detected by machine and generates a report on its discoveries.

More information about the tool is available from the Ace web site.


The Accessible Rich Internet Applications (ARIA) specification addresses the problem of making modern script-heavy web applications accessible for users of assistive technologies. These applications often do not use the built-in HTML elements, like buttons, in their interfaces, but turn otherwise static content, like images, into objects that users can click on to perform actions. While this is done to make the interfaces more visually appealing, prior to ARIA the scripting necessary to make these features work were not reflected in the accessibility tree. The result was to make such interfaces impossible to use.

ARIA addresses this problem by defining roles, states and properties so that the static elements can be presented like their more natural counterparts (e.g., a role of button can be assigned to an image so that assistive technologies can make it interactive).

Refer to the ARIA specification for more information.

Assistive Technology

An assistive technology (AT) is a device or software program capable of rendering content in ways that facilitate reading by persons with disabilities.

An assistive technology may be fully integrated into a reading system or may work in conjunction with hardware and software to provide a reading experience better tailored to the reader's preferred modality (e.g., screen-reading software like JAWS and NVDA, content zooming technologies and refreshable braille displays).


The person or organization directly responsible for creating a digital publication and ensuring the quality and accessibility of the final product.

In the context of digital publication specifications and documentation, the "author" does not refer to the person who wrote a publication. It is used to avoid personal pronouns (specifically "you"), as personal pronouns make translation to other languages more complex.