Simple Event Dispatcher to register any Object or DOM element to listen for custom events and take appropriate action based on who dispatched it.

JavaScript Event Dispatcher

/*
  Simple Event Dispatcher
  Author : Stephen Braitsch
	
------------------------------------------------------------------
	Example Usage :
	
		var MY_CUSTOM_EVENT = 'my-custom-event';
	
		var myObj = { name : 'stephen'};
		myObj.dispatch(MY_CUSTOM_EVENT);
		
		function onCustomEvent(evt)
		{
			console.log(evt.type, evt.target);
		// prints : MY_CUSTOM_EVENT, { name : 'stephen'};
		}
		
		window.addListener(MY_CUSTOM_EVENT, onCustomEvent);
		
------------------------------------------------------------------
	Example Usage w/ jQuery :
	
		var MY_CUSTOM_EVENT = 'my-custom-event';
		
		$('#myDiv).click(function(){
			$(this).dispatch(MY_CUSTOM_EVENT);
		})
		
		function onCustomEvent(evt)
		{
			if (evt.target.attr(id) == 'myDiv'){
				console.log('you clicked myDiv);
			}
		}
		
		window.addListener(MY_CUSTOM_EVENT, onCustomEvent);
*/

window.EventDispatcher = new function(){

	var __events = [];

	Object.defineProperty(Object.prototype, "addListener", { 
		value: function(e, f) {
			for (var i = __events.length - 1; i >= 0; i--){
		// check if this event is already registered with the dispatcher //
				if (__events[i].name == e){
				// if it is, check if this object is already registered to listen for the event //
					for (var k = __events[i].listeners.length - 1; k >= 0; k--){
						if (__events[i].listeners[k].obj == this) {
							console.log(this + 'is already registered to listen for '+e);
							return;
						}
					};
				// if the dispatcher already knows about the event, but this object is not yet registered to listen for it, let's add it.
					__events[i].listeners.push({obj:this, func:f});
		//			console.log('registering '+this+' to listen for '+e);
					return;
				}
			};
		// if this event is not yet registered with the dispatcher add it to the events array //
		//	console.log('listening for a new event '+e);
			__events.push({name : e, listeners:[{obj:this, func:f}]});
		},
		enumerable : false
	});

	Object.defineProperty(Object.prototype, "removeListener", { 
	    value: function(e) {
			for (var i = __events.length - 1; i >= 0; i--){
				if (__events[i].name == e){
					for (var k = __events[i].listeners.length - 1; k >= 0; k--){
						if (__events[i].listeners[k].obj == this) __events[i].listeners.splice(k, 1);
					};
				}
			}
		},
		enumerable : false
	});
	
	Object.defineProperty(Object.prototype, "dispatch", {
		value: function(e) {
			for (var i = __events.length - 1; i >= 0; i--){
				if (__events[i].name == e){
					for (var k = __events[i].listeners.length - 1; k >= 0; k--){
						__events[i].listeners[k].func({type:e, target:this});
					};
				}
			};
		},
		enumerable : false
	});

};