function valign(elementId, containerHeight) {
	if (document.getElementById) {
		if (containerHeight > 0) {
			var element = document.getElementById(elementId);
			var elementHeight = element.offsetHeight;
			if (containerHeight - elementHeight > 0) {
				element.style.position = 'relative';
				element.style.top = ((containerHeight / 2) - (elementHeight / 2)) + 'px';
			}
		}
	}
}