function zeigemenu1() {
document.getElementById("umenu1").style.display = "block";
document.getElementById("umenu2").style.display = "none";
document.getElementById("umenu3").style.display = "none";
}

function zeigemenu2() {
document.getElementById("umenu1").style.display = "none";
document.getElementById("umenu2").style.display = "block";
document.getElementById("umenu3").style.display = "none";
}

function zeigemenu3() {
document.getElementById("umenu1").style.display = "none";
document.getElementById("umenu2").style.display = "none";
document.getElementById("umenu3").style.display = "block";
}