function akt(nr,zs)
 {
  var ima="mg"+nr;
  var txt="mt"+nr;
  var neu;
  var art;
  neu = new Image(); 
  if (zs == 0)
   {
    neu.src = "grafik/pfiw.gif";
    art = "underline"
   }
  else if (zs == 1)
   {
    neu.src ="grafik/pfis.gif";
    art = "none"
   }
  if (navigator.appName == 'Microsoft Internet Explorer')
   {
    document.images[ima].src = neu.src;
    document.all[txt].style.textDecoration = art;
   }
  else if (navigator.appName == 'Netscape')
   {
    var lay="me"+nr;
    document.layers[lay].document.images[ima].src = neu.src;
   }
 }