function slideShow(nr) {
 var obj1=document.getElementById("sl01");
 var obj2=document.getElementById("sl02");
 if ((obj1)&&(obj2)) {
  if (obj1.style.display=="none") {
   obj1.style.display="block";
   obj2.style.display="none";
  }
  else {
   obj1.style.display="none";
   obj2.style.display="block";
  }
  setTimeout("slideShow(" + nr + ");",7500);
 }
}