Understanding screen reader interaction modes
21 September 2014
- Code things
Traduction française
Windows screen readers have multiple modes of interaction, and depending on the task being carried out they’ll automatically switch to the most appropriate mode. This post explains why Windows screen readers behave the way they do, and how your code can influence that behaviour.
Virtual/browse mode
When a document is rendered in the browser, Windows screen readers like JAWS and NVDA access the Document Object Model (DOM) either directly or through the available accessibility APIs. The DOM is a hierarchical representation of the objects in the web-document, and the information that’s retrieved from it is augmented by the screen reader and displayed to the user as a virtual copy of the original.
By creating a virtual copy of the document, screen readers make it possible for blind people to interact with content in ways that would otherwise be impossible on the Windows platform. This happens because the screen reader intercepts most keypresses before they reach the browser, triggering an interaction with the virtual document instead.
For example the left/right cursor keys are intercepted and used to move focus to the previous/next character in the content, and the up/down keys move focus to the previous/next [...]