menu_items = 5;

function showmenu(show){
	
	for(i=1; i<=menu_items; i++){
		document.getElementById("dd_" + i).style.display = "none";
	}
	
	document.getElementById("dd_" + show).style.display = "block";
	
}

function hidemenu(){
	for(i=1; i<=menu_items; i++){
		document.getElementById("dd_" + i).style.display = "none";
	}
}