function auf(menu) {

// DOM ALLE NEUEN BROWSER
if (document.getElementById) {
document.getElementById(menu).style.visibility="visible";
}

// IE 5

if (document.all) {
document.all[menu].style.visibility="visible";
}

// NN 4
if (document.layers) {
document.layers[menu].visibility="visible";
}
}

function zu(menu) {


if (document.getElementById) {
document.getElementById(menu).style.visibility="hidden";
}


if (document.all) {
document.all[menu].style.visibility="hidden";
}

if (document.layers) {
document.layers[menu].visibility="hidden";
}
}