I looking out javascript expert.

I need to capture the event triggered by dragging and dropping a bookmark onto the window, preferably in all browsers. What I actually need is the target url of the bookmark. onbeforeunload does get triggered, but the event has no information about the target URL and I can't stop the page from loading it either. mouseup also does not work.

The FileReader API seems viable, but I'm not sure whether it's appropriate. Ideally this would also work in at least IE9 (which does not support FileReader).