JQuery: how can I find out when a tab / window gets focus?

Question

Is there an event that I can register for this, every time a user clicks on a tab, which means that they were on my page tab, clicked on another tab, and then returned to my tab.

EDIT: By tabs, I mean browser tabs, not jQueryUI tabs.

Answer 1

Matijis provided this answer in a comment, but I wanted to accept it, so here it is as an answer.

$(window).on('focus', function() { // your code }); 

Answer 2

Try using jquery $ (selector) .focusin or: focus, they work the same.

http://api.jquery.com/focusin/

http://api.jquery.com/focus-selector/