function imageswitch() {
   var numimg = 185;

   var milli = new Date().getTime();
   var hour = milli / 1000 / 60 / 60;
   var indeximg = Math.floor(hour % numimg);
   
   var formatted = "" + indeximg;
   while (formatted.length < 4) {
      formatted = "0"+formatted;
   } 
   var filename = "/START/st"+formatted+".jpg";
   
   if (document.URL.indexOf("hauptseite") != -1) {

      var allimg = document.getElementsByTagName('img');
      
      for (loop = 0;loop < allimg.length;loop++) {
         thisimg = allimg[loop];
         if (thisimg.title == '470er') {

            thisimg.src = filename;
            
         }
      }	

   }
   
}



window.onload=imageswitch;