var active = false;
function showMenu(who) {
	if(active) {
		document.getElementById("sub_" + active).style.display = "none";
		document.getElementById("link_" + active).className= "";
		active = false;
	}
	
	if(document.getElementById("sub_" + who)) {
		document.getElementById("sub_" + who).style.display = "block";
		document.getElementById("link_" + who).className= "active";
		active = who;
	}
	
}