var top;
  var base;
  var pos;
  var speedy;
  speedy = 1;
  
  function Iniciar() {
    top = document.all.Layer1.offsetHeight + 3;
    base = 0 - (document.all.Layer2.offsetHeight + 3);
    pos = parseInt(document.all.Layer2.style.top);
    Mover();
  }
  function Mover() {
    pos = pos - 2;
    document.all.Layer2.style.top=pos;
    if (pos<base) { pos=top;}
    if (speedy==1) {
      setTimeout("Mover()",100)
    }
  }
  window.onload = Iniciar