Cross-browser: detect blur event on window

Question

I just read, I think all the thread that deals with this subject, and I can\'t find a real solution to my problem. I need to detect when the browser window loses its focus, i.e.

Answer 1

The document.hasFocus (MDN) is an implementation that can resolve the problem with Firefox, but in Opera it isn't supported. So, a combined approach can reach out the problem you are facing.

The function below exemplifies how can you use this method:

function getDocumentFocus() {
    return document.hasFocus();
}

Since your question isn't clear enough about the application (timed, pub/sub system, event driven, etc), you can use the function above in several ways.

For example, a timed verification can be like the one implemented on this fiddle (JSFiddle).