function einblenden(id){
  var obj = document.getElementById(id);
  obj.style.display='block';
}
function ausblenden(id){
  var obj = document.getElementById(id);
  obj.style.display='none';
}

function zeigen(x,y){
  var obj = document.getElementById('kreis');
  obj.style.visibility='visible';
  obj.style.top=y+'px';
  obj.style.left=x+'px';
}

function zeigen2(x,y){
  var obj = document.getElementById('kreis2');
  if (obj){
    obj.style.visibility='visible';
    obj.style.top=y+'px';
    obj.style.left=x+'px';
  }
}