function elementToMiddle(objID,parentObj) {
	var pH = $(parentObj).getHeight();
	var oH = $(objID).getHeight();
	if(pH > oH) {
		$(objID).setStyles({
			'position':'relative',
			'top': ((pH - oH) / 2) + 'px',
			'marginBottom': '0px'
		});
	} else {
		$(objID).setStyles({'top': '0px'});
	}
}

window.addEvent('domready', function() {
	elementToMiddle('box',window);
	$(window).addEvents({'resize' : function(){elementToMiddle('box',window);}});
});