var xb =
{
	evtHash: [],

	ieGetUniqueID: function(_elem)
	{
		if (_elem === window) { return 'theWindow'; }
		else if (_elem === document) { return 'theDocument'; }
		else { return _elem.uniqueID; }
	},

	addEvent: function(_elem, _evtName, _fn, _useCapture)
	{
		if (typeof _elem.addEventListener != 'undefined')
		{
			if (_evtName == 'mouseenter')
				{ _elem.addEventListener('mouseover', xb.mouseEnter(_fn), _useCapture); }
			else if (_evtName == 'mouseleave')
				{ _elem.addEventListener('mouseout', xb.mouseEnter(_fn), _useCapture); } 
			else
				{ _elem.addEventListener(_evtName, _fn, _useCapture); }
		}
		else if (typeof _elem.attachEvent != 'undefined')
		{
			var key = '{FNKEY::obj_' + xb.ieGetUniqueID(_elem) + '::evt_' + _evtName + '::fn_' + _fn + '}';
			var f = xb.evtHash[key];
			if (typeof f != 'undefined')
				{ return; }
			
			f = function()
			{
				_fn.call(_elem);
			};
		
			xb.evtHash[key] = f;
			_elem.attachEvent('on' + _evtName, f);
	
			// attach unload event to the window to clean up possibly IE memory leaks
			window.attachEvent('onunload', function()
			{
				_elem.detachEvent('on' + _evtName, f);
			});
		
			key = null;
			//f = null;   /* DON'T null this out, or we won't be able to detach it */
		}
		else
			{ _elem['on' + _evtName] = _fn; }
	},	

	removeEvent: function(_elem, _evtName, _fn, _useCapture)
	{
		if (typeof _elem.removeEventListener != 'undefined')
			{ _elem.removeEventListener(_evtName, _fn, _useCapture); }
		else if (typeof _elem.detachEvent != 'undefined')
		{
			var key = '{FNKEY::obj_' + xb.ieGetUniqueID(_elem) + '::evt' + _evtName + '::fn_' + _fn + '}';
			var f = xb.evtHash[key];
			if (typeof f != 'undefined')
			{
				_elem.detachEvent('on' + _evtName, f);
				delete xb.evtHash[key];
			}
		
			key = null;
			//f = null;   /* DON'T null this out, or we won't be able to detach it */
		}
	},
	
	mouseEnter: function(_pFn)
	{
		return function(_evt)
		{
			var relTarget = _evt.relatedTarget;				
			if (this == relTarget || xb.isAChildOf(this, relTarget))
				{ return; }

			_pFn.call(this, _evt);
		}
	},
	
	isAChildOf: function(_parent, _child)
	{
		if (_parent == _child) { return false };
		
		while (_child && _child != _parent)
			{ _child = _child.parentNode; }
		
		return _child == _parent;
	}	
};