/* -----------------------------------------------------------------------------------
 *	Events 	Events handling
 *	
 *		Required: none
 *
 * -----------------------------------------------------------------------------------
 *	
 *		addEvent( element, type, handler )
 *		removeEvent( element, type, handler )
 *				
 *		Add event methods
 *
 *			preventDefault
 *			stopPropagation
 *
 * -----------------------------------------------------------------------------------
 */

var Events = {};

/* 	written by Dean Edwards, 2005
 	with input from Tino Zijdel, Matthias Miller, Diego Perini

 	http://dean.edwards.name/weblog/2005/10/add-event/
*/

/* ---------------------------------------------------------------------------------
 *		Public functions
 * --------------------------------------------------------------------------------- */

function addEvent(element, type, handler) {
	if (element.addEventListener) {
		element.addEventListener(type, handler, false);
	} else {
		/* assign each event handler a unique ID */
		if (!handler.$$guid) handler.$$guid = addEvent.guid;
		addEvent.guid++;
		/* create a hash table of event types for the element */
		if (!element.events) element.events = {};
		/* create a hash table of event handlers for each element/event pair */
		var handlers = element.events[type];
		if (!handlers) {
			handlers = element.events[type] = {};
			/* store the existing event handler (if there is one) */
			if (element["on" + type]) {
				handlers[0] = element["on" + type];
			}
		}
		/* store the event handler in the hash table */
		handlers[handler.$$guid] = handler;
		/* assign a global event handler to do all the work */
		element["on" + type] = handleEvent;
	}
};
	/* a counter used to create unique IDs */
	addEvent.guid = 1;
function removeEvent(element, type, handler) {
	if (element.removeEventListener) {
		element.removeEventListener(type, handler, false);
	} else {
		/* delete the event handler from the hash table */
		if (element.events && element.events[type]) {
			delete element.events[type][handler.$$guid];
		}
	}
};


/* ---------------------------------------------------------------------------------
 *		Private functions
 * --------------------------------------------------------------------------------- */

function handleEvent(event) {
	var returnValue = true;
	/* grab the event object (IE uses a global event object) */
	event = event || fixEvent(((this.ownerDocument || this.document || this).parentWindow || window).event);
	/* get a reference to the hash table of event handlers */
	var handlers = this.events[event.type];
	/* execute each event handler */
	for (var i in handlers) {
		this.$$handleEvent = handlers[i];
		if (this.$$handleEvent(event) === false) {
			returnValue = false;
		}
	}
	return returnValue;
};
function fixEvent(event) {
	/* add W3C standard event methods */
	event.preventDefault = fixEvent.preventDefault;
	event.stopPropagation = fixEvent.stopPropagation;
	return event;
};
fixEvent.preventDefault = function() {
	this.returnValue = false;
};
fixEvent.stopPropagation = function() {
	this.cancelBubble = true;
};