function addEvent(el, evType, fn) {
  if (el.addEventListener) {
    el.addEventListener(evType, fn, false);
    return true;
  } else if (el.attachEvent) {
    var r = el.attachEvent('on' + evType, fn);
    return r;
  } else {
    el['on' + type] = fn;
    return true;
  }
}