function setCenterPosition(outer, inner) {
		inner.style.left = "-500";
		inner.style.display = '';
		var inner_width = inner.offsetWidth;
		var inner_height = inner.offsetHeight;
		inner.style.display = 'none';
		inner.style.left = (outer.offsetWidth - inner_width) / 2;
		inner.style.top = (outer.offsetHeight - inner_height) / 2;
	}