function set_middle ()
{
	if (!document.getElementById || !document.body.offsetHeight) return;
	var window_height = typeof(window.innerHeight) == 'number' ? window.innerHeight : (document.documentElement && document.documentElement.clientHeight) ? document.documentElement.clientHeight : (document.body && document.body.clientHeight) ? document.body.clientHeight : 0;
	var content = document.getElementById('container');
	var content_height = content.offsetHeight;
	if (window_height < content_height)
	{
		content.style.marginTop = 30 + 'px';
		content.style.marginBottom = 30 + 'px';
	}
	else
	{
		content.style.marginTop = ((window_height -  content_height ) / 2 ) + 'px';
	}
}

window.onload = set_middle;
window.onresize = set_middle;