"Keyboard trap" is an implementation that makes it impossible to escape from keyboard operation when focus shifts to an element. When creating a modal window etc., you have to be able to do it not only with the mouse but also with the keyboard to close it.
Principle | Operable | User interface components and navigation must be operable. |
---|---|---|
Guideline | Keyboard Accessible | Make all functionality available from a keyboard. |
Criterion | No Keyboard Trap (2.1.2 A) |
If the keyboard interface can be used to move the keyboard focus to a component of the webpage, it is possible to remove focus from that component using only the keyboard interface. Furthermore, if you can not remove focus by using arrow keys without a modifier key, Tab key, or other standard method of removing focus, the user is notified of the method of removing focus. |