I am having strange problem with jQuery (1.6.x). I have this simple call on my page:

```
window.onbeforeunload = function() { return 'Are you sure ?'; };

```

But it doesn't work, because as I've found out, jQuery overwrites content of the `window.onbeforeunload`. In JS console, I can see that `window.onbeforeunload` contains piece of jQuery code:

```
function( e ) {
// Discard the second event of a jQuery.event.trigger() and
// when an event is called after a page has unloaded
return typeof jQuery !== "undefined" && (!e || jQuery.event.triggered !== e.type) ?
    jQuery.event.handle.apply( eventHandle.elem, arguments ) : undefined;
};

```

Is there a way I can find why and where jQuery overwrites my `onbeforeunload` function? When I try to run empty jsfiddle with just jQuery loaded and with my `onbeforeunload` function, it works as expected. 

Any hints will be appreciated. 

EDIT: 

Just in case, somebody suggests using: 

```
$(window).bind('beforeunload', function() { return 'Are you sure';} );

```

I've already tried it and it behaves the same way as using pure Javascript.