If keyboard focus can be moved to a component of the page using a keyboard interface, then focus can be moved away from that component using only a keyboard interface, and, if it requires more than unmodified arrow or tab keys or other standard exit methods, the user is advised of the method for moving focus away. (Level A)
Note: Since any content that does not meet this success criterion can interfere with a user’s ability to use the whole page, all content on the Web page (whether it is used to meet other success criteria or not) must meet this success criterion.
Web pages are formed with a group of components. Calendars, plug-in, flash components, model windows etc are few among them. In order to make these components available to every user authors ensure that these components are accessible with keyboard. When these components are navigated with keyboard, a mechanism should be in place to navigate away with keyboard alone without depending on mouse or other pointing devices.
When some custom components are built in web pages the screen reader mode will be changed from browse mode to more comfortable mode to best interact with that component. Components such as grid, tree grid, flash etc cannot be accessed with general key commands.
Have a look at the Grid example from Illinois university (External website)to have a better understanding. The content authors have explained how to navigate into the grid, within the grid and exit from the grid as the mode of interaction with the web page changes while interacting with the grid component.
Some authors create overlays without a close button. The user navigates throughout the layer and will not be able to come out of the layer since the layer does not have a close button. It means the user is trapped in the layer and will not be able to exit. Ensure a mechanism such as escape is in place to close the layer and the same is intimated to the user.
- Ensure that the keyboard focus is not trapped within subsections or components of the web page.
- When focus to any component is made available with the keyboard, ensure that navigating away from that component also should be available with keyboard alone.
- When accessing any component needs special key commands, that should be intimated to the user in advance.
- Ensure that the same mechanism used to navigate into the component is used to navigate away after navigating through all the elements of the component as much as possible.
- Ensure that using mouse or any pointing device should not be the sole way of exiting any component or subset of the page.
Note: If the problem of keyboard trap exist in the page users will not be able to access any other elements of the page.