var speedz=3
  var step=100
  var movespeed=15
  var MyMarz;

  function MarqueezDown(){
    var demo1z = document.getElementById('demo1z');
    var demoz = document.getElementById('demoz');
    if(demo1z.offsetHeight-demoz.scrollTop-50<=0)
      demoz.scrollTop=demo1z.offsetHeight-50
    else
      demoz.scrollTop+=movespeed
  }

  function MarqueezTop(){
    var demo1z = document.getElementById('demo1z');
    var demoz = document.getElementById('demoz');
    if(demoz.scrollTop<=0)
      demoz.scrollTop=0
    else
      demoz.scrollTop-=movespeed
  }

  function MoveDown()
  {
    var demo1z = document.getElementById('demo1z');
    var demoz = document.getElementById('demoz');
    if(demo1z.offsetHeight-demoz.scrollTop-93>0)
    {
      var downbutton=document.getElementById('downbutton');
      downbutton.src='images/bln/down.jpg';
      MyMarz=setInterval(MarqueezDown,speedz)
      setTimeout("clearInterval(MyMarz)", speedz*step*3/movespeed)
      setTimeout(clearInterval, speedz*step*3/movespeed, MyMarz)
      //setTimeout("var downbutton=document.getElementById('downbutton');leftbutton.src='images/bln/down.jpg'", speedz*step*3/movespeed)
    }
  }

  function MoveTop()
  {
    var demo1z = document.getElementById('demo1z');
    var demoz = document.getElementById('demoz');
    if(demoz.scrollTop>0)
    {
      var upbutton=document.getElementById('upbutton');
      upbutton.src='images/bln/up.jpg'
      MyMarz=setInterval(MarqueezTop,speedz)
      setTimeout("clearInterval(MyMarz)", speedz*step*3/movespeed)
      setTimeout(clearInterval, speedz*step*3/movespeed, MyMarz)
      //setTimeout("rightbutton.src='images/bln/up.jpg'", speedz*step*3/movespeed)
    }
  }