function showOverlay() {
	overlay = new Element('div', {'id': 'overlay'}).inject(document.body, 'top');
	overlay.setStyle('height', document.getScrollSize().y);
	overlay.set('opacity', 0.5);
	if(window.ie) $$('select').set('visibility','hidden');
	return false;
}

function hideOverlay() {
	overlay.remove();
	document.removeEvents();
	if(window.ie) $$('select').setStyle('visibility','visible');
	return false;
}