function showDiv(obj) {
        hideDiv();
        document.getElementById(obj).style.visibility = "visible";
    }

function showDiv2(obj) {
        document.getElementById(obj).style.visibility = "visible";
    }
    
            
function hideDiv() {
        document.getElementById("willkommen").style.visibility = "hidden";       
        document.getElementById("preise").style.visibility = "hidden";              
        document.getElementById("umgebung").style.visibility = "hidden";          
        document.getElementById("service").style.visibility = "hidden";   
  }