function addevent(obj, ev, func) {
	if (obj.addEventListener) obj.addEventListener(ev, func, false);
	else if (obj.attachEvent) obj.attachEvent("on" + ev, func);
	obj = null;
}
function deleteevent(obj, ev, func) {
	if (obj.removeEventListener) obj.removeEventListener(ev, func, false);
	else if (obj.detachEvent) obj.detachEvent("on" + ev, func);
	obj = null;
}