What the standard says
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.
Why it matters
A trap ends the session. A keyboard user who cannot Tab out of a widget has no way back short of reloading the page.
What a failure looks like
- failsA modal that loops focus but has no Escape handler and no close button in the loop.
- failsAn embedded third-party player that swallows Tab.
How to fix it
- doIn a modal, trap focus deliberately *and* close on Escape, with a reachable close button.
- doTest every embed with the keyboard before you ship it.
How A11ySignal checks it
manual
No automated rule can judge this criterion, and we will not pretend otherwise. A clean scan does not mean 2.1.2 passes — it means nothing we can measure fails. This one needs a person.
What a tool cannot tell you
Traps are found by tabbing through the page, not by scanning it.