var agt=navigator.userAgent.toLowerCase();
NS4 = (document.layers && (agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1) && (agt.indexOf('compatible') == -1) && (agt.indexOf('msie') == -1) && (agt.indexOf('netscape6') == -1)) ? 1 : 0;
NS6 = (agt.indexOf('netscape6') != -1) ? 1 : 0;
IE4 = (document.all && navigator.appVersion.indexOf("Mac") == -1) ? 1 : 0;
trackInterval = 30;
windowPos = 240;
if (!NS4) layerButton.style.pixelTop = 240;

function slide() {
  YOffset = (NS4) ? window.pageYOffset : document.body.scrollTop;
  if (YOffset <= windowPos && windowPos == 240) return;
  if (YOffset > windowPos) {
    deltaY = Math.ceil(Math.abs(YOffset - windowPos) / 8);
    if (NS4) document.layerButton.top += deltaY;
    else layerButton.style.pixelTop += deltaY;
    windowPos += deltaY;
  }
  else {
    if (YOffset > 240) {
      deltaY = Math.ceil(Math.abs(YOffset - windowPos) / 8);
    }
    else {
      deltaY = Math.ceil(Math.abs(240 - windowPos) / 8);
    }
    if (NS4) document.layerButton.top -= deltaY;
    else layerButton.style.pixelTop -= deltaY;
    windowPos -= deltaY;
  }
}

track = setInterval("slide();", 30);