<SCRIPT type="text/javascript">
function scrollpage() {
    function scroll() {
    Height= document.body.scrollHeight;
      if (status == 0) {
        i = i + 10;
        window.scrollBy(0, 20);
        if (i >= Height) {
          status = 1;
          i=Height;
          window.scrollBy(0, -40);
        }
      } else {
        i = i - 10;
    window.scrollBy(0, -20);
        if (i <= 1) {
          status = 0;
        }
      }
      setTimeout(scroll, 50);
    }
    scroll();
  }
var Height;
var i = 1,status = 0;
window.onload=scrollpage
</SCRIPT>