title: Has window.onload fired yet?
body: <p>I have a script that will be inserted into an unknown page at an unknown time.  Is it possible to tell from this script if window.onload has fired yet?</p>
  
  <p>I have no control over the host page.  I can't add any markup or scripts to it.  All I know is that my script will be inserted into the page at some point.  It could be before window.onload or after; and I need to detect which side of that event I'm on.</p>