function blau() {
  zelle=document.getElementsByTagName('td');
  links=document.getElementsByTagName('a');
  for (var i = 4; i <= zelle.length; i++)
  {
  if (zelle[i])
  {
  if (zelle[i].className=="navi")
  zelle[i].className="navi2";}
  }

  for (var i = 0; i <= links.length; i++)
  {
  if (links[i])
  {  if (links[i].className=="grau")
  links[i].className="nav2";}  }
  
  }
function grau() {
  zelle=document.getElementsByTagName('td');
  links=document.getElementsByTagName('a');

  for (var i = 4; i <= zelle.length; i++)
  {if (zelle[i])
  {
  if (zelle[i].className=="navi2")
  zelle[i].className="navi";
  }} 
  for (var i = 0; i <= links.length; i++)
  {
  if (links[i])
  {  if (links[i].className=="nav2")
  links[i].className="grau";}  }
  
  } 
  
  function dblau(li)
  {
  document.getElementsByTagName('a')[li].className="nav";
  document.getElementsByTagName('td')[5+li*2].className="navili";

  }
  
  function hblau(li)
  {
  document.getElementsByTagName('a')[li].className="nav2";
  document.getElementsByTagName('td')[5+li*2].className="navi2";
  }  
  
  function dblau_u(li)
  {
  document.getElementsByTagName('td')[5+li*2].className="navili";
  }
  
  function hblau_u(li)
  {
  document.getElementsByTagName('td')[5+li*2].className="navi2";
  }