function showhide_menu(sh_which){  
	var sh_elemente = sh_getElementsByClassName ("submenu_item");
	for (var i = 0; i<sh_elemente.length; i++) {
		sh_elemente[i].style.display = "none";
	}
	document.getElementById(sh_which).style.display = "block";
}

function sh_getElementsByClassName (sh_c) {
	var sh_array = [];
	var sh_tags = document.getElementsByTagName("div");
	var j = 0;
	for (var i = 0; i<sh_tags.length; i++) {
		if (sh_tags[i].className==sh_c) {
			sh_array[j] = sh_tags[i];
			j++;
		}
	}
	return sh_array;
}