Cài đặt phần trăm thanh cuộn (Scrollbar) cho Blogspot

#scroll {
  display:none;
  position:fixed;
  top:0;
  right:15px;
  z-index:500;
  padding:3px 8px;
  background-color:#369fcf;
  color:#fff;
  border-radius:3px;
  font-size:14px;  
}
#scroll:after {
  content: " ";
  position: absolute;
  top:50%;
  right:-10px;
  height:0;
  width:0;
  margin-top:-6px;
  border:6px solid transparent;
  border-left-color:#369fcf;
}  

<div id='scroll'></div>  

<script type='text/javascript'>
//<![CDATA[
var scrollTimer = null;
$(window).scroll(function() {
   var viewportHeight = $(this).height(),
       scrollbarHeight = viewportHeight / $(document).height() * viewportHeight,
       progress = $(this).scrollTop() / ($(document).height() - viewportHeight),
       distance = progress * (viewportHeight - scrollbarHeight) + scrollbarHeight / 2 - $('#scroll').height() / 2;
    $('#scroll')
        .css('top', distance)
        .text(' (' + Math.round(progress * 100) + '%)')
        .fadeIn(600);
    if (scrollTimer !== null) {
        clearTimeout(scrollTimer);
    }
    scrollTimer = setTimeout(function() {
        $('#scroll').fadeOut(600);
    }, 1000);
});
//]]>
</script>