title: Can I pop up a confirmation dialog when the user is closing the window in Safari/Chrome?
body: <p>In IE and FF, i can attach an event handler to onBeforeUnload, and by passing a string to a property of the event, the user will see a dialog asking him whether he wants to continue with the "unloading" (either closing the window or navigating away).</p>
  
  <p>Safari and Chrome don't support onBeforeUnload, and onUnload seems to be too late.
  Is there some way to replicate the same functionality in Safari/Chrome?</p>
  
  <p>NOTE: I'm not trying to keep the user hostage. I know this is nagging and un-cool. In fact, my site goes to great lengths to let the user go freely, and have everything in its place when they come back.
  However, I am hosting other sites inside IFrames, and sometimes these decide to get rid of me and take over the browser, which is what I'm trying to avoid.</p>
  
  <p>Thanks!</p>