wrappedJSObject-woodoo.user.js

window.addEventListener('load', function(){
  //Works in Opera
  //Doesnt' work in Greasemonkey
  alert('window')
}, false)

window.wrappedJSObject.addEventListener('load', function(){
  //Doesn't work in Opera
  //Works in Greasemonkey. See http://wiki.greasespot.net/UnsafeWindow
  alert('wrappedJSObject')
}, false)

var w = window.wrappedJSObject || window;
w.addEventListener('load', function(){
  //Works in Opera and Greasemonkey!
  alert('window.wrappedJSObject || window')
}