JS: Attach Event Listener

//////////////////
////ATTACH EVENT LISTENER
/////////////////
function attachEventListener(eventTarget, eventType, eventHandler) {
	if (eventTarget.addEventListener) {
		eventTarget.addEventListener(eventType, eventHandler, false);
	} else if (eventTarget.attachEvent) {
		eventType = "on" + eventType;
		eventTarget.attachEvent(eventType, eventHandler);
	} else {
		eventTarget["on" + eventType] = eventHandler;
	}
};