function showmenu(n) {
	for (i=1; i<=4; i++) {
		mid = "menu"+i;
		el = document.getElementById(mid);
		if (i==n) {
			el.style.visibility="visible";
		} else {
			el.style.visibility="hidden";
	}
}
return;
}

function hidemenu(n) {
	var mid = "menu"+n;
	var thisel = document.getElementById(mid);
	thisel.style.visibility="hidden";
	return;
}

function hideall() {
	for (i=1; i<=4; i++) {
		mid = "menu"+i;
		el = document.getElementById(mid);
		el.style.visibility="hidden";
	}
}