var floatingMenuId = 'floatdiv';
var contHeight = document.getElementById('content').clientHeight;

var floatingMenu =
{
	targetY: 15,

	hasInner: typeof(window.innerWidth) == 'number',
	hasElement: typeof(document.documentElement) == 'object'
		&& typeof(document.documentElement.clientWidth) == 'number',

	menu:
		document.getElementById
		? document.getElementById(floatingMenuId)
		: document.all
		  ? document.all[floatingMenuId]
		  : document.layers[floatingMenuId]
};

floatingMenu.move = function ()
{
	floatingMenu.menu.style.top = floatingMenu.nextY + 'px';
}

floatingMenu.computeShifts = function ()
{
	var de = document.documentElement;

	floatingMenu.shiftY = 
		floatingMenu.hasInner
		? pageYOffset
		: floatingMenu.hasElement
		  ? de.scrollTop
		  : document.body.scrollTop;
	if (floatingMenu.targetY < 0)
	{
		if (floatingMenu.hasElement && floatingMenu.hasInner)
		{
			floatingMenu.shiftY +=
				de.clientHeight > window.innerHeight
				? window.innerHeight
				: de.clientHeight
		}
		else
		{
			floatingMenu.shiftY +=
				floatingMenu.hasElement
				? de.clientHeight
				: document.body.clientHeight;
		}
	}
}

floatingMenu.calculateCornerY = function()
{
	if (floatingMenu.targetY != 'center')
		return floatingMenu.shiftY + floatingMenu.targetY;

	var height = parseInt(floatingMenu.menu.offsetHeight);

	var clientHeight = 
		floatingMenu.hasElement && floatingMenu.hasInner
		&& document.documentElement.clientHeight 
			> window.innerHeight
		? window.innerHeight
		: document.documentElement.clientHeight

	var cornerY =
		floatingMenu.hasElement
		? (floatingMenu.hasInner  
		   ? pageYOffset
		   : document.documentElement.scrollTop) + 
		  (clientHeight - height)/2
		: document.body.scrollTop + 
		  (document.body.clientHeight - height)/2;
	return cornerY;
};

floatingMenu.doFloat = function()
{
	var stepY;

	floatingMenu.computeShifts();


	var cornerY = floatingMenu.calculateCornerY();
	if (contHeight < 500) { contHeight = 500; }
	if (cornerY > contHeight-165) { cornerY = contHeight-165 };

	var stepY = (cornerY - floatingMenu.nextY) * .07;
	if (Math.abs(stepY) < .5)
	{
		stepY = cornerY - floatingMenu.nextY;
	}

	if (Math.abs(stepY) > 0)
	{
		floatingMenu.nextY += stepY;
		floatingMenu.move();
	}

	setTimeout('floatingMenu.doFloat()', 20);
};

floatingMenu.addEvent = function(element, listener, handler)
{
	if(typeof element[listener] != 'function' || 
	   typeof element[listener + '_num'] == 'undefined')
	{
		element[listener + '_num'] = 0;
		if (typeof element[listener] == 'function')
		{
			element[listener + 0] = element[listener];
			element[listener + '_num']++;
		}
		element[listener] = function(e)
		{
			var r = true;
			e = (e) ? e : window.event;
			for(var i = element[listener + '_num'] -1; i >= 0; i--)
			{
				if(element[listener + i](e) == false)
					r = false;
			}
			return r;
		}
	}

	for(var i = 0; i < element[listener + '_num']; i++)
		if(element[listener + i] == handler)
			return;
	element[listener + element[listener + '_num']] = handler;
	element[listener + '_num']++;
};

floatingMenu.init = function()
{
	floatingMenu.initSecondary();
	floatingMenu.doFloat();
};

floatingMenu.initSecondary = function()
{
	floatingMenu.computeShifts();
	floatingMenu.nextY = floatingMenu.calculateCornerY();
	floatingMenu.move();
}

if (document.layers)
	floatingMenu.addEvent(window, 'onload', floatingMenu.init);
else
{
	floatingMenu.init();
	floatingMenu.addEvent(window, 'onload',
		floatingMenu.initSecondary);
}