var delta = 0;
  var timer;
  var interval = 40;

  function scrollL(){
    delta = -5;
    timer = setInterval("move()", interval);
  }

  function scrollR(){
    delta = 5;
    timer = setInterval("move()", interval);
  }

  function scrollStop(){
    clearInterval(timer);
  }

  function move(){
    scrolldiv =  document.getElementById('tgs');
    //balra
    var left = scrolldiv.scrollLeft;
    var width = scrolldiv.scrollWidth;

    if ((delta < 0 ) && ( left <  10 )){
      //bal
      left = left + width/2 ;
    }      
    if ((delta > 0) && ( left > width / 2 )) {
      //jobb
      left = left - width/2;
    }
//    document.title= left+delta;
    scrolldiv.scrollLeft = left + delta;
  }