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