function addOnload(onloadFunc) {
  // based on http://answers.google.com/answers/threadview?id=510976
  if(this.addEventListener) {
    this.addEventListener("load", onloadFunc, false);
  } else if(this.attachEvent) {
    this.attachEvent("onload", onloadFunc);
  } else {
    var onloadOld = this.onload;
    this.onload = function() { onloadOld(); onloadFunc(); }
  }
}