var EventHelpers = new function () {
	var me = this;

	var safariTimer;
	var isSafari = /WebKit/i.test(navigator.userAgent);
	
	/**
	 * Adds an event to the document.  Examples of usage: 
	 * me.addEvent(window, "load", myFunction);
	 * me.addEvent(docunent, "keydown", keyPressedFunc);
	 * me.addEvent(document, "keyup", keyPressFunc);
	 * 
	 * @author Scott Andrew - http://www.scottandrew.com/weblog/articles/cbs-events
	 * @author John Resig - http://ejohn.org/projects/flexible-javascript-events/
	 * @param {Object} obj - a javascript object.
	 * @param {String} evType - an event to attach to the object.
	 * @param {Function} fn - the function that is attached to the event.
	 */
	me.addEvent = function (obj, evType, fn){
	  
	  if (obj.addEventListener){
		obj.addEventListener(evType, fn, false);
	  } else if (obj.attachEvent){
		obj['e'+evType+fn] = fn;
		obj[evType+fn] = function() { obj["e"+evType+fn]( self.event ); }
		obj.attachEvent( "on"+evType, obj[evType+fn] );
	  } 
	}
	
	
	/**
	 * Removes an event that is attached to a javascript object.
	 * 
	 * @author Scott Andrew - http://www.scottandrew.com/weblog/articles/cbs-events
	 * @author John Resig - http://ejohn.org/projects/flexible-javascript-events/	 * @param {Object} obj - a javascript object.
	 * @param {String} evType - an event attached to the object.
	 * @param {Function} fn - the function that is called when the event fires.
	 */
	me.removeEvent = function (obj, evType, fn){
	
	  if (obj.removeEventListener){
	    obj.removeEventListener(evType, fn, false);
	  } else if (obj.detachEvent){
	  	try {
			obj.detachEvent("on"+evType, obj[evType+fn]);
			obj[evType+fn] = null;
			obj["e" + evType + fn] = null;
		} catch (ex) {
			// do nothing;
		}
	  }
	}
	
	function removeEventAttribute(obj, beginName) {
		var attributes = obj.attributes;
		for (var i=0; i<attributes.length; i++) {
			var attribute = attributes[i]
			var name = attribute.name
			if (name.indexOf(beginName) == 0) {
				//obj.removeAttributeNode(attribute);
				attribute.specified = false;
			}
		}
	} 

	me.addScrollWheelEvent = function (obj, fn) {
		if (obj.addEventListener) {
        	/** DOMMouseScroll is for mozilla. */
        	obj.addEventListener('DOMMouseScroll', fn, true);
		} 
		
		/** IE/Opera. */
		if (obj.attachEvent) {
			obj.attachEvent("onmousewheel", fn);
		}
		
	}
	
	me.removeScrollWheelEvent = function (obj, fn) {
		if (obj.removeEventListener) {
        	/** DOMMouseScroll is for mozilla. */
        	obj.removeEventListener('DOMMouseScroll', fn, true);
		} 
		
		/** IE/Opera. */
		if (obj.detachEvent) {
			obj.detatchEvent("onmousewheel", fn);
		}
		
	}
	
	/**
	 * Given a mouse event, get the mouse pointer's x-coordinate.
	 * 
	 * @param {Object} e - a DOM Event object.
	 * @return {int} - the mouse pointer's x-coordinate.
	 */
	me.getMouseX = function (e)
	{	
		if (!e) {
			return;
		}
		// NS4
		if (e.pageX != null) {
			return e.pageX;
		// IE
		} else if (window.event != null && window.event.clientX != null 
				&& document.body != null && 
				document.body.scrollLeft != null)
			return window.event.clientX + document.body.scrollLeft;
		// W3C
		else if (e.clientX != null) 
			return e.clientX;
		else 
			return null;
	}
	
	/**
	 * Given a mouse event, get the mouse pointer's y-coordinate.
	 * @param {Object} e - a DOM Event Object.
	 * @return {int} - the mouse pointer's y-coordinate.
	 */
	me.getMouseY = function (e)
	{
		// NS4
		if (e.pageY != null )
			return e.pageY;
		// IE
		else if (window.event != null  && window.event.clientY != null  && 
				document.body != null  &&
				document.body.scrollTop != null )
			return window.event.clientY + document.body.scrollTop; 
		// W3C
		else if (e.clientY != null) {
			return e.clientY;
		}
	}
	/**
	 * Given a mouse scroll wheel event, get the "delta" of how fast it moved.
	 * @param {Object} e - a DOM Event Object.
	 * @return {int} - the mouse wheel's delta.  It is greater than 0, the 
	 * scroll wheel was spun upwards; if less than 0, downwards.
	 */	
	me.getScrollWheelDelta = function(e){
        var delta = 0;
        if (!e) /* For IE. */
                e = window.event;
        if (e.wheelDelta) { /* IE/Opera. */
				delta = e.wheelDelta/120;
				/** In Opera 9, delta differs in sign as compared to IE.
				 */
				if (window.opera) {
					delta = -delta ;
				}
        } else if (e.detail) { /** Mozilla case. */
                /** In Mozilla, sign of delta is different than in IE.
                 * Also, delta is multiple of 3.
                 */
                delta = -e.detail/3;
        }
		return delta
	}
	
	/**
	 * Sets a mouse move event of a document.  
	 * 
	 * @deprecated - use only if compatibility with IE4 and NS4 is necessary.  Otherwise, just 
	 * 		use EventHelpers.addEvent(window, 'mousemove', func) instead. Cannot be used to add
	 * 		multiple mouse move event handlers.
	 * 
	 * @param {Function} func - the function that you want a mouse event to fire.
	 */
	me.addMouseEvent = function (func) {
		
		if (document.captureEvents){
			document.captureEvents(Event.MOUSEMOVE);
		}
		
		document.onmousemove = func;
		window.onmousemove = func;
		window.onmouseover=func;
		
	}
	
	
	
	/** 
	 * Find the HTML object that fired an Event.
	 * 
	 * @param {Object} e - an HTML object
	 * @return {Object} - the HTML object that fired the event.
	 */
	me.getEventTarget = function (e) {	
		// first, IE method for mouse events(also supported by Safari and Opera)
		if (e.toElement) {
			return e.toElement;
		// W3C
		} else if (e.currentTarget) {
			return e.currentTarget;
	
		// MS way
		} else if (e.srcElement) {
			return e.srcElement;
		} else {
			return null;
		}
	}
	
	


	/**
	 * Given an event fired by the keyboard, find the key associated with that event.
	 * 
	 * @param {Object} e - an event object.
	 * @return {String} - the ASCII character code representing the key associated with the event.
	 */
	
	me.getKey = function (e)
	{
		if (e.keyCode) {
			return e.keyCode;
		} else if (e.event && e.event.keyCode) { 
			return window.event.keyCode;
		} else if (e.which) {
			return e.which;
		}
	}
	
	
	/** 
	*  Will execute a function when the page's DOM has fully loaded (and before all attached images, iframes,
	*  etc., are).  
	*  
	*  Usage:
	*  
	*  EventHelpers.addPageLoadEvent('init');
	*
	*  where the function init() has this code at the beginning:
	*
	*  function init() {
	*
	*  if (EventHelpers.hasPageLoadHappened(arguments)) return;
	*
	*	// rest of code
	*   ....
	*  }
	*
	* @author This code is based off of code from http://dean.edwards.name/weblog/2005/09/busted/ by Dean 
	* Edwards, with a modification by me.
	* 
	* @param {String} funcName - a string containing the function to be called.  
	*/
	me.addPageLoadEvent = function (funcName) {
		
		var func = eval(funcName);
		
		// for Internet Explorer (using conditional comments)
		/*@cc_on @*/
		/*@if (@_win32)
		pageLoadEventArray.push(func);
		return;
		/*@end @*/
		if (isSafari) { // sniff
			pageLoadEventArray.push(func);
			
			if (!safariTimer) {
				
				safariTimer = setInterval(function(){
					if (/loaded|complete/.test(document.readyState)) {
						clearInterval(safariTimer);
						
						/*
						 * call the onload handler
						 * func();
						 */
						me.runPageLoadEvents();
						return;
					}
					set = true;
				}, 10);
			}
		/* for Mozilla */
		} else if (document.addEventListener) {
			var x =document.addEventListener("DOMContentLoaded", 
				func, null);
		
		/* Others */
		} else {
			me.addEvent(window, 'load', func);
		} 
	}
		
	var pageLoadEventArray = new Array();
	
	me.runPageLoadEvents = function (e) {
		if (isSafari || e.srcElement.readyState == "complete" ) {
			
			for (var i=0; i<pageLoadEventArray.length; i++) {	
				pageLoadEventArray[i]();
			}
		}
	} 
	/**
	 * Determines if either addPageLoadEvent('funcName') or addEvent(window, 'load', funcName)
	 * has been executed.
	 * 
	 * @see addPageLoadEvent
	 * @param {Function} funcArgs - the arguments of the containing. function
	 */
	me.hasPageLoadHappened = function (funcArgs) {
		// If the function already been called, return true;
		if (funcArgs.callee.done) return true;
	
		// flag this function so we don't do the same thing twice
		funcArgs.callee.done = true;
	}
	
	
	
	/**
	 * Used in an event method/function to indicate that the default behaviour of the event
	 * should *not* happen.
	 * 
	 * @param {Object} e - an event object.
	 * @return {Boolean} - always false
	 */
	me.preventDefault = function (e) {
		
	    if(e.preventDefault)
	    {
	        e.preventDefault();
	    }
		
	    try {
	        e.returnValue = false;
	    } catch (ex) {
			// do nothing
		}
	
	}
	
	me.cancelBubble = function (e) {
		if(e.stopPropagation)
	    {
	        e.stopPropagation();
	    }
		
	    try {
	        e.cancelBubble = true;
	    } catch (ex) {
			// do nothing
		}
	}

	/* EventHelpers.init () */
	function init() {
		// Conditional comment alert: Do not remove comments.  Leave intact.
		// The detection if the page is secure or not is important. If 
		// this logic is removed, Internet Explorer will give security
		// alerts.
		/*@cc_on @*/
		/*@if (@_win32)
		document.write('<script id="__ie_onload" defer src="' + 
			((location.protocol == 'https:') ? '//0' : 'javascript:void(0)') + '"><\/script>');
		var script = document.getElementById("__ie_onload");
		me.addEvent(script, 'readystatechange', me.runPageLoadEvents);
		/*@end @*/
	}
	
	init();	
}