var picnum = 1;

function setStartPageImg()
{ 
  var x=document.getElementById("imageStartpage"); 
  switch(picnum)
  { 
    case 1: imgId="1"; imgSrc="/home/images/startseite/start1.jpg"; changeImage("imageStartpage", imgId, imgSrc); break; 
    case 2: imgId="2"; imgSrc="/home/images/startseite/start2.jpg"; changeImage("imageStartpage", imgId, imgSrc); break;
    case 3: imgId="3"; imgSrc="/home/images/startseite/start3.jpg"; changeImage("imageStartpage", imgId, imgSrc); break;  
    default: imgId="3"; imgSrc="/home/images/startseite/start1.jpg"; changeImage("imageStartpage", imgId, imgSrc); break; 
  }
  
  picnum++;
  if(picnum > 3)
    picnum= 1;
    
  window.setTimeout("setStartPageImg()", 3000);
}