// window.onload W3C cross-browser with a fallback
function addLoadEvent(func) {
  if (window.addEventListener)
    window.addEventListener("load", func, false);
  else if (window.attachEvent)
    window.attachEvent("onload", func);
  else { // fallback
    var old = window.onload;
    window.onload = function() {
      if (old) old();
      func();
    };
  }
}