Javascript to detect if user changes tab

Question

I want to write a webpage for online quiz.Basic requirement i have is that, If the person taking quiz changes tab or opens new window even without minimizing browser, i.

Answer 1

If you are targeting browsers that support it, you can use the Page Visibility API available in HTML5. It doesn't directly detect tab changes, per-say, but visibility changes. Which would include (but not limited to) tab changes.

See https://developer.mozilla.org/en/DOM/Using_the_Page_Visibility_API