MUI 返回顶部

         //绑定滚动到顶部按钮事件
         if ($("#scroll-up").length > 0) {

             var scrollToTopBox = $("#scroll-up"), isVisible = false;
             $(window).on("scroll.btnScrollTop", function() {
                 var scroll = $(window).scrollTop(), h = $(window).height(), sh = document.body.scrollHeight;
                 if (scroll > parseInt(h / 4) || (scroll > 0 && sh >= h && h + scroll >= sh - 1)) {
                     if (!isVisible) {
                         scrollToTopBox.addClass("display");
                         isVisible = true
                     }
                 } else {
                     if (isVisible) {
                         scrollToTopBox.removeClass("display");
                         isVisible = false
                     }
                 }
             }).triggerHandler("scroll.btnScrollTop");
             mui('body').on('tap', '#scroll-up', function(e) {
                 e.stopPropagation();
                 window.scrollTo(0, 0, 100);

             })
         }

    <a id="scroll-up" href="#" class="btn btn-sm">
        <span class="mui-icon mui-icon-arrowup"></span>
    </a>

CSS

 #scroll-up {
     border-width:;
     position: fixed;
     right: 2px;
     z-index:;
     -webkit-transition-duration: .3s;
     transition-duration: .3s;
     opacity:;
     filter: alpha(opacity=0);
     bottom: -24px;
     visibility: hidden;
     background-color: #aaa;
     color: #fff;
     font-size: 14px
 }

 #scroll-up.display {
     opacity: .7;
     filter: alpha(opacity=70);
     bottom: 2px;
     visibility: visible
 }

 #scroll-up:hover {
     opacity:;
     filter: alpha(opacity=100)
 }

 #scroll-up:focus {
     outline: 0
 }

其中字体文件需要替换为例自己的ttf文件，另外在

 <span class="mui-icon mui-icon-arrowup"></span>
里面的class也修改为例想要的即可，实测Android IOS 均可