function addEvent(elm, evType, fn, useCapture) {
	// addEvent and removeEvent
	// cross-browser event handling for IE5+,  NS6 and Mozilla
	// By Scott Andrew
	if (elm.addEventListener) {
		elm.addEventListener(evType, fn, useCapture);
		return true;
	} else if (elm.attachEvent) {
		var r = elm.attachEvent("on"+evType, fn);
		return r;
	} else {
		return false;
	}
}