i = 0;
var speed = 2;
function scroll() {
 i = i + speed;
 try {
  var div = document.getElementById("advertBox_vert");
  div.scrollTop = i;
  
  /*if( i > 1350) {
  alert(i+"----"+(div.scrollHeight/2 ));
  }
  */
  if( i >= div.scrollHeight / 2 + 29 ) {
   i = 0;
  }
  
  //alert(div.offsetHeight );
  
  if (i > div.scrollHeight - div.clientHeight ) {
   //alert(div.scrollHeight + "----" + i); 
   speed = speed * -1;
   clearTimeout(t1);
   t1=setTimeout("wait()",1000);
  } else if ( i < 0 ) {
   speed = speed * -1;
   clearTimeout(t1);
   t1=setTimeout("wait()",1000);
  } else {
   t1=setTimeout("scroll()",50);
  }
 } 
 catch(err) {
  t1=setTimeout("wait()",1000);
 }
}
function wait() {
 scroll();
// alert("teszt");
}

function roll_over(img_name, img_src) {
 document[img_name].src = img_src;
 
}

scroll();