In plain English
This is the natural partner to the keyboard rule: not only must you be able to Tab into things, you must be able to Tab back out. If focus goes into a modal, a video player, or a menu and then gets stuck cycling forever inside it, a keyboard user is trapped, with no mouse to rescue them.
The fix is usually straightforward: let Tab move out normally, and make Escape close overlays and return focus to where it was.
Who this is for
- Keyboard and screen-reader users, who have no mouse to click their way out of a stuck widget.
- Everyone, occasionally, when a poorly built popup hijacks the keyboard.
What “good” looks like
Focus enters, moves around, and can always leave.
Open a modal → Tab cycles through its buttons → Escape closes it
and returns focus to the button that opened it. ✓
Tab into a video player → Tab continues past it to the
next link on the page (not stuck on the controls). ✓Where stores get it wrong
Custom modals that loop focus with no Escape, third-party chat or review widgets that swallow the keyboard, and embedded players that never let Tab move on. If you find focus stuck anywhere during a keyboard pass, it is on the common failures list and needs fixing before checkout can be completed by keyboard.