vis1 = "";
  vis2 = "";
  
  function close_me(obj){
   (document.getElementById(obj)).style.visibility="hidden";
   }
 
  function show_object(obj){
   (document.getElementById(obj)).style.visibility="visible";
   }
  
  function show_level1(num){
   if (vis2){
    close_me("marker" + vis2);
    close_me("list" + vis2);
    }
    
   if (vis1){
    close_me("marker" + vis1);
    close_me("list" + vis1);
    }

   show_object("marker" + num);
   show_object ("list" + num);
   vis2 = "";
   vis1 = num;
   }

  function show_level2(num){
   if (vis2){
    close_me("marker" + vis2);
    close_me("list" + vis2);
    }
    
   show_object("marker" + num);
   show_object ("list" + num);
   vis2 = num;
   }
   
  function openwin(name){
   self.open('data/' + name + '.html', 'prov', 'width=620,height=430,scrollbars=no,resizable=no,toolbars=location');
   }

  function openscrollwin(name){
   self.open('data/' + name + '.html', 'prov', 'width=620,height=430,scrollbars=yes,resizable=no,toolbars=location');
   }