function DisplayMenu(obj,act) {
	obj=document.getElementById(obj);
	if (act) {
		obj.style.visibility='visible';
	} else {
		obj.style.visibility='hidden';
	}
}


function showmenu(height) {
	if (!height) return;
	document.getElementById('pos').style.top=(height-document.getElementById('pos').clientHeight)/2;
	document.getElementById('pos').style.visibility='visible';
}