This script is used for going to top of the page you are viewing.

gotop_of_page

$(document).ready(function(){
    var $backToTopTxt = "返回顶部"
    var $backToTopEle = $('<div class="backToTop"></div>').appendTo($(".site"))
    .text($backToTopTxt).attr("title", $backToTopTxt).click(
        function() {
            $("html, body").animate({ scrollTop: 0 }, 120);
        }), 
        $backToTopFun = function() {
            var st = $(document).scrollTop(), winh = $(window).height();
            (st > 500)? $backToTopEle.show(): $backToTopEle.hide();    
            //IE6下的定位
            if (!window.XMLHttpRequest) {
                $backToTopEle.css("top", st + winh - 166);    
            }
        };
    $(window).bind("scroll", $backToTopFun);
    $(function() { $backToTopFun(); });
});
 
.backToTop { 
  display: none;
  width: 18px;
  line-height: 1.2;
  padding: 5px 0;
  background-color: #000;
  color: #fff;
  font-size: 12px;
  text-align: center;
  position: fixed;
  right: 28%;
  bottom: 100px;
  cursor: pointer;
}