function getWindowHeight()
{
	if (self.innerWidth)
		{
			return self.innerHeight;
				}
					else if (document.documentElement && document.documentElement.clientWidth)
						{
							return document.documentElement.clientHeight;
						}
					else if (document.body)
				{
			return document.body.clientHeight;
		} 
	return 0;
}
function onResize () {
	var container = document.getElementById ("container_div");
	var page = document.getElementById("page");
	
	var h = getWindowHeight ();
	page.style.height = (h - 5) + "px";
	container.style.top = (h/2-container.offsetHeight/2-5) + "px";
}
window.onresize = onResize;