javascript - Confirmation before closing of tab/browser

Question

How to ask confirmation from user before he leaves the page as in gmail?

I searched for this question in various places, but all that they mention is the use of javascript window.unload & window.onbeforeunload. Also it doesn't work in chrome most of the times as it gets blocked.

Answer 1

Try this:

<script>
window.onbeforeunload = function (e) {
    e = e || window.event;

    // For IE and Firefox prior to version 4
    if (e) {
        e.returnValue = 'Sure?';
    }

    // For Safari
    return 'Sure?';
};
</script>

Here is a working jsFiddle