if (document.images)
 {
   nexton= new Image();
   nexton.src="fileadmin/img/prevnext/next_over.png";  

   nextoff= new Image();
   nextoff.src="fileadmin/img/prevnext/next.png";
   
   prevon= new Image();
   prevon.src="fileadmin/img/prevnext/prev_over.png";  

   prevoff= new Image();
   prevoff.src="fileadmin/img/prevnext/prev.png";
 }

function lightup(imgName)
 {
   if (document.images)
    {
      imgOn=eval(imgName + "on.src");
      //alert(imgOn)
      document.images[imgName].src=imgOn;
      document.images[imgName+'2'].src=imgOn;
    }
 }

function turnoff(imgName)
 {
   if (document.images)
    {
      imgOff=eval(imgName + "off.src");
      document.images[imgName].src=imgOff;
      document.images[imgName+'2'].src=imgOff;
    }
 }