Is there a reliable way to determine if a browser tab or window is inactive or not in focus?

Question

I\'ve got a javascript timer that is making XMLHTTP requests on a constant basis (once every 10 seconds). I\'d love to be able to pause the timer when the window or tab los

Answer 1

My previous desperate attempts to find such a thing have led me to conclude that there is no such animal.

Oh, how I would love to be wrong.