<script src="http://cdn.bootcss.com/scrollup/2.4.0/jquery.scrollUp.min.js"></script>

$(function () {
   $.scrollUp({
       scrollName:"scrollUp",
       topDistance:"300",
       topSpeed:300,
       animation:"fade",
       animationInSpeed:200,
       animationOutSpeed:200,
       scrollText:'<i class="fa fa-angle-up"></i>',
       activeOverlay:!1
   });
});

/*返回顶部样式*/
#scrollUp {
   background-color: #777;
   color: #eee;
   font-size: 40px;
   line-height: 1;
   text-align: center;
   text-decoration: none;
   bottom: 20px;
   right: 20px;
   overflow: hidden;
   width: 46px;
   height: 46px;
   border: none;
   opacity: .8;
}

#scrollUp:hover{background-color:#333}
@media screen and (min-width:992px){#scrollUp{bottom:80px}}