function ReturnDimensions() 
{
	var dim = new Array(0, 1);
	
	if (typeof(window.innerWidth) == 'number') 
	{
		//Non-IE
		dim[0] = window.innerWidth;
		dim[1] = window.innerHeight;
	} 
	else if (document.documentElement && (document.documentElement.clientWidth || document.documentElement.clientHeight)) 
	{
		//IE 6+ in 'standards compliant mode'
		dim[0] = document.documentElement.clientWidth;
		dim[1] = document.documentElement.clientHeight;
	} 
	else if (document.body && (document.body.clientWidth || document.body.clientHeight)) 
	{
		//IE 4 compatible
		dim[0] = document.body.clientWidth;
		dim[1] = document.body.clientHeight;
	}
	
	return dim;
}

function Center()
{
	var layer = document.getElementById('container');
	
	var height = ReturnDimensions();
	
	layer.style.top = (height[1] - 600) / 2 + 'px';
	
}