What is a focus trap and when do you need one?
PICTURE THIS: HOW TO EXPLAIN IT
Simple meaning
A focus trap keeps Tab cycling inside a modal so keyboard users do not escape into the page behind.
WHY — A11y instead of guessing?
Why interviewers care about A11y:
who only read docs from people who shipped.
and tied to Frontend work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1A focus trap keeps
Tab cycling inside a modal so keyboard users do not escape into the page behind.
- 2I restore focus to
the opener on close.
- 3Without it, modals fail
basic accessibility.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
A focus trap keeps Tab cycling inside a modal so keyboard users do not escape into the page behind. I restore focus to the opener on close.