Custom Events Java Script

  function EventSystem() {
		this.eventListeners = {};
	}

	EventSystem.prototype.on = function(eventType, eventHandler) {
		
		if(typeof this.eventListeners[eventType] === "undefined") {
			this.eventListeners[eventType] = [];
		}

		this.eventListeners[eventType].push(eventHandler);
	};


	/**
	 * Custom Event Triger
	 */
	EventSystem.prototype.triger = function(eventObject) {
		
		if(typeof eventObject.type === "undefined") {
			throw new {
				message : "Unspecifaid EventTypeExcepion"
			}
		}

		if(typeof eventObject.target === "undefined") {
			eventObject.target = this;
		}

		var getAllListeners = this.eventListeners[eventObject.type];

		if(typeof getAllListeners === "undefined") {
			return;
		}

		for(var i = 0; i< getAllListeners.length; i++) {
			getAllListeners[i].call(this, eventObject);
		}
	};