function change(a) {
  document.getElementById('bild').src = "Bilder/Startseite/"+a;
}

var a = 0;

function show_menu(area) {

if (a == 1) {
  oldlist.childNodes[1].style.display="none"; 
}

  mylist = document.getElementById(area);


  if(mylist.childNodes[1].style.display=="none" || mylist.childNodes[1].style.display==""){ 
      mylist.childNodes[1].style.display="block";}
  else { mylist.childNodes[1].style.display="none"; }

  a = 1;
  oldlist = document.getElementById(area);

}