Keyboard focus must not be trapped

Rule keyboard-trap · Component patterns (best practice) · impact critical · Live only (static → incomplete)

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Why it matters#

If pressing Tab stops moving focus — because a component swallows the key, or a modal contains focus with no escape — keyboard and screen-reader users are stranded. The engine Tabs through the live page and reports where focus stopped advancing.

How to fix#

Ensure every component lets focus move out with Tab/Shift+Tab. For modals, trap focus only while open and restore it on close (and support Escape).

Example#

<input onkeydown="if(event.key==='Tab')event.preventDefault()">

<input>

WCAG success criteria#

2.1.2 No Keyboard Trap — Level A#

Keyboard focus must never get stuck: a user who tabs into a component must be able to tab (or use a documented key) back out of it.

Understanding 2.1.2

Standards#

This rule contributes to the following standards:

WCAG A EN 301 549 Best practice

References#

• WCAG — No Keyboard Trap