2.1.2 - No keyboard trap

The intent of this success criterion is to ensure that the keyboard focus doesn't get "trapped" within any subsections of content on a web page. This is a common problem when multiple formats are combined within a page and rendered using plug-ins or embedded applications.

Ensure that at any point, the user is able to exit any page functionality without having to resort to using the Esc key or refreshing the browser and that they are able to  navigate to and from all navigable page elements using only a keyboard.

This can be achieved by:

• using device independent event handlers (works with both the mouse and the keyboard)
• applying both mouse dependent and keyboard dependent event handlers