EventBus.js

var EventBusClass = {};
EventBusClass = function() {
	this.listeners = {};
};
EventBusClass.prototype = {
	addEventListener:function(type, callback, scope) {
		var args = [];
		var numOfArgs = arguments.length;
		for(var i=0; i<numOfArgs; i++){
			args.push(arguments[i]);
		}		
		args = args.length > 3 ? args.splice(3, args.length-1) : [];
		if(typeof this.listeners[type] != "undefined") {
			this.listeners[type].push({scope:scope, callback:callback, args:args});
		} else {
			this.listeners[type] = [{scope:scope, callback:callback, args:args}];
		}
	},
	removeEventListener:function(type, callback, scope) {
		if(typeof this.listeners[type] != "undefined") {
			var numOfCallbacks = this.listeners[type].length;
			var newArray = [];
			for(var i=0; i<numOfCallbacks; i++) {
				var listener = this.listeners[type][i];
				if(listener.scope == scope && listener.callback == callback) {
					
				} else {
					newArray.push(listener);
				}
			}
			this.listeners[type] = newArray;
		}
	},
	dispatch:function(type, target) {
		var numOfListeners = 0;
		var event = {
			type:type,
			target:target
		};
		var args = [];
		var numOfArgs = arguments.length;
		for(var i=0; i<numOfArgs; i++){
			args.push(arguments[i]);
		};				
		args = args.length > 2 ? args.splice(2, args.length-1) : [];
		args = [event].concat(args);
		if(typeof this.listeners[type] != "undefined") {
			var numOfCallbacks = this.listeners[type].length;
			for(var i=0; i<numOfCallbacks; i++) {
				var listener = this.listeners[type][i];
				if(listener && listener.callback) {
					listener.args = args.concat(listener.args);
					listener.callback.apply(listener.scope, listener.args);
					numOfListeners += 1;
				}
			}
		}
	},
	getEvents:function() {
		var str = "";
		for(var type in this.listeners) {
			var numOfCallbacks = this.listeners[type].length;
			for(var i=0; i<numOfCallbacks; i++) {
				var listener = this.listeners[type][i];
				str += listener.scope && listener.scope.className ? listener.scope.className : "anonymous";
				str += " listen for '" + type + "'\n";
			}
		}
		return str;
	}
};
var EventBus = new EventBusClass();