How to subscribe an event

You can subscribe an event just through calling BTTEventMng.prototype.addListener(eventName, fn, scope), in which fn represents the event listener and scope represents the namespace of the listener. Take the following block of code as an example:
var em = new BTTEventMng();
em.addEvents("event1","event2");//publish two events named “event1” and “event2”
em.addListener("event1",listener,window);
function listener(arg){
	//alert(arg);
}