function addEvent(obj, evType, fn){
  if (obj.addEventListener){
    obj.addEventListener(evType, fn, true);
    return true;
  }
  else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  }
  else {
	return false;
  }
}
function removeEvent( obj, type, fn ) {
	if ( obj.detachEvent ) {
		obj.detachEvent( 'on'+type, fn );
		obj[type+fn] = null;
	}
	else{
		eval("obj.removeEventListener(type,fn,true)");
	}
}