function createWin(loc,pg) {
	newWin = window.open(loc,'nav_win',
'left=20,top=20,toolbar=no,location=no,directories=no,status=yes,menubar=no,scrollbars=yes,resizable=yes,width=500,height=500');
	newWin.creator = self;
}

function bo(name) {
  bild=new Image();
  if(name=="def") adr="/pics/aquarium.jpg";
  else adr="/pics/aquarium-"+name+".jpg";
  document.mainpic.src=bild.src;
}
function bu(name) {
  bild=new Image();
  if(name=="def") adr="/pics/aquarium.jpg";
  else adr="/pics/aquarium-"+name+".jpg";
  document.obenpic.src=bild.src;
}
function show(name) {
  bild=new Image();
  if(name=="def") adr="/pics/aquarium.jpg";
  else adr="/pics/aquarium-"+name+".jpg";
  top.document.obenpic.src=adr;
}