给自己网站放一个返回顶部js特效效果把，主要是图片素材也不错，比较抢镜，所以弄个小教程，比较简单，放上去试试看把

演示效果：本站

首先，主要代码如下

<div class="back-to-top cd-top faa-float animated" ></div>

这里代码放在，一般是底部foot的文件里面，具体位置底部就行，faa-float是自然状态的摇曳抖动的效果

样式css的配置：

/*gotop*/

@media (max-width:1000px){.back-to-top{display:none!important;}}
@-webkit-keyframes wrench{0%{-webkit-transform:rotate(-12deg);transform:rotate(-12deg)}8%{-webkit-transform:rotate(12deg);transform:rotate(12deg)}10%{-webkit-transform:rotate(24deg);transform:rotate(24deg)}18%,20%{-webkit-transform:rotate(-24deg);transform:rotate(-24deg)}28%,30%{-webkit-transform:rotate(24deg);transform:rotate(24deg)}38%,40%{-webkit-transform:rotate(-24deg);transform:rotate(-24deg)}48%,50%{-webkit-transform:rotate(24deg);transform:rotate(24deg)}58%,60%{-webkit-transform:rotate(-24deg);transform:rotate(-24deg)}68%{-webkit-transform:rotate(24deg);transform:rotate(24deg)}100%,75%{-webkit-transform:rotate(0deg);transform:rotate(0deg)}}@keyframes wrench{0%{-webkit-transform:rotate(-12deg);-ms-transform:rotate(-12deg);transform:rotate(-12deg)}8%{-webkit-transform:rotate(12deg);-ms-transform:rotate(12deg);transform:rotate(12deg)}10%{-webkit-transform:rotate(24deg);-ms-transform:rotate(24deg);transform:rotate(24deg)}18%,20%{-webkit-transform:rotate(-24deg);-ms-transform:rotate(-24deg);transform:rotate(-24deg)}28%,30%{-webkit-transform:rotate(24deg);-ms-transform:rotate(24deg);transform:rotate(24deg)}38%,40%{-webkit-transform:rotate(-24deg);-ms-transform:rotate(-24deg);transform:rotate(-24deg)}48%,50%{-webkit-transform:rotate(24deg);-ms-transform:rotate(24deg);transform:rotate(24deg)}58%,60%{-webkit-transform:rotate(-24deg);-ms-transform:rotate(-24deg);transform:rotate(-24deg)}68%{-webkit-transform:rotate(24deg);-ms-transform:rotate(24deg);transform:rotate(24deg)}100%,75%{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg)}}.faa-parent.animated-hover:hover>.faa-wrench,.faa-wrench.animated,.faa-wrench.animated-hover:hover{-webkit-animation:wrench 2.5s ease infinite;animation:wrench 2.5s ease infinite;transform-origin-x:90%;transform-origin-y:35%;transform-origin-z:initial}.faa-parent.animated-hover:hover>.faa-wrench.faa-fast,.faa-wrench.animated-hover.faa-fast:hover,.faa-wrench.animated.faa-fast{-webkit-animation:wrench 1.2s ease infinite;animation:wrench 1.2s ease infinite}.faa-parent.animated-hover:hover>.faa-wrench.faa-slow,.faa-wrench.animated-hover.faa-slow:hover,.faa-wrench.animated.faa-slow{-webkit-animation:wrench 3.7s ease infinite;animation:wrench 3.7s ease infinite}@-webkit-keyframes ring{0%{-webkit-transform:rotate(-15deg);transform:rotate(-15deg)}2%{-webkit-transform:rotate(15deg);transform:rotate(15deg)}4%{-webkit-transform:rotate(-18deg);transform:rotate(-18deg)}6%{-webkit-transform:rotate(18deg);transform:rotate(18deg)}8%{-webkit-transform:rotate(-22deg);transform:rotate(-22deg)}10%{-webkit-transform:rotate(22deg);transform:rotate(22deg)}12%{-webkit-transform:rotate(-18deg);transform:rotate(-18deg)}14%{-webkit-transform:rotate(18deg);transform:rotate(18deg)}16%{-webkit-transform:rotate(-12deg);transform:rotate(-12deg)}18%{-webkit-transform:rotate(12deg);transform:rotate(12deg)}100%,20%{-webkit-transform:rotate(0deg);transform:rotate(0deg)}}@keyframes ring{0%{-webkit-transform:rotate(-15deg);-ms-transform:rotate(-15deg);transform:rotate(-15deg)}2%{-webkit-transform:rotate(15deg);-ms-transform:rotate(15deg);transform:rotate(15deg)}4%{-webkit-transform:rotate(-18deg);-ms-transform:rotate(-18deg);transform:rotate(-18deg)}6%{-webkit-transform:rotate(18deg);-ms-transform:rotate(18deg);transform:rotate(18deg)}8%{-webkit-transform:rotate(-22deg);-ms-transform:rotate(-22deg);transform:rotate(-22deg)}10%{-webkit-transform:rotate(22deg);-ms-transform:rotate(22deg);transform:rotate(22deg)}12%{-webkit-transform:rotate(-18deg);-ms-transform:rotate(-18deg);transform:rotate(-18deg)}14%{-webkit-transform:rotate(18deg);-ms-transform:rotate(18deg);transform:rotate(18deg)}16%{-webkit-transform:rotate(-12deg);-ms-transform:rotate(-12deg);transform:rotate(-12deg)}18%{-webkit-transform:rotate(12deg);-ms-transform:rotate(12deg);transform:rotate(12deg)}100%,20%{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg)}}.faa-parent.animated-hover:hover>.faa-ring,.faa-ring.animated,.faa-ring.animated-hover:hover{-webkit-animation:ring 2s ease infinite;animation:ring 2s ease infinite;transform-origin-x:50%;transform-origin-y:0;transform-origin-z:initial}.faa-parent.animated-hover:hover>.faa-ring.faa-fast,.faa-ring.animated-hover.faa-fast:hover,.faa-ring.animated.faa-fast{-webkit-animation:ring 1s ease infinite;animation:ring 1s ease infinite}.faa-parent.animated-hover:hover>.faa-ring.faa-slow,.faa-ring.animated-hover.faa-slow:hover,.faa-ring.animated.faa-slow{-webkit-animation:ring 3s ease infinite;animation:ring 3s ease infinite}@-webkit-keyframes vertical{0%{-webkit-transform:translate(0,-3px);transform:translate(0,-3px)}4%{-webkit-transform:translate(0,3px);transform:translate(0,3px)}8%{-webkit-transform:translate(0,-3px);transform:translate(0,-3px)}12%{-webkit-transform:translate(0,3px);transform:translate(0,3px)}16%{-webkit-transform:translate(0,-3px);transform:translate(0,-3px)}20%{-webkit-transform:translate(0,3px);transform:translate(0,3px)}100%,22%{-webkit-transform:translate(0,0);transform:translate(0,0)}}@keyframes vertical{0%{-webkit-transform:translate(0,-3px);-ms-transform:translate(0,-3px);transform:translate(0,-3px)}4%{-webkit-transform:translate(0,3px);-ms-transform:translate(0,3px);transform:translate(0,3px)}8%{-webkit-transform:translate(0,-3px);-ms-transform:translate(0,-3px);transform:translate(0,-3px)}12%{-webkit-transform:translate(0,3px);-ms-transform:translate(0,3px);transform:translate(0,3px)}16%{-webkit-transform:translate(0,-3px);-ms-transform:translate(0,-3px);transform:translate(0,-3px)}20%{-webkit-transform:translate(0,3px);-ms-transform:translate(0,3px);transform:translate(0,3px)}100%,22%{-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)}}.faa-parent.animated-hover:hover>.faa-vertical,.faa-vertical.animated,.faa-vertical.animated-hover:hover{-webkit-animation:vertical 2s ease infinite;animation:vertical 2s ease infinite}.faa-parent.animated-hover:hover>.faa-vertical.faa-fast,.faa-vertical.animated-hover.faa-fast:hover,.faa-vertical.animated.faa-fast{-webkit-animation:vertical 1s ease infinite;animation:vertical 1s ease infinite}.faa-parent.animated-hover:hover>.faa-vertical.faa-slow,.faa-vertical.animated-hover.faa-slow:hover,.faa-vertical.animated.faa-slow{-webkit-animation:vertical 4s ease infinite;animation:vertical 4s ease infinite}@-webkit-keyframes horizontal{0%{-webkit-transform:translate(0,0);transform:translate(0,0)}6%{-webkit-transform:translate(5px,0);transform:translate(5px,0)}12%{-webkit-transform:translate(0,0);transform:translate(0,0)}18%{-webkit-transform:translate(5px,0);transform:translate(5px,0)}24%{-webkit-transform:translate(0,0);transform:translate(0,0)}30%{-webkit-transform:translate(5px,0);transform:translate(5px,0)}100%,36%{-webkit-transform:translate(0,0);transform:translate(0,0)}}@keyframes horizontal{0%{-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)}6%{-webkit-transform:translate(5px,0);-ms-transform:translate(5px,0);transform:translate(5px,0)}12%{-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)}18%{-webkit-transform:translate(5px,0);-ms-transform:translate(5px,0);transform:translate(5px,0)}24%{-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)}30%{-webkit-transform:translate(5px,0);-ms-transform:translate(5px,0);transform:translate(5px,0)}100%,36%{-webkit-transform:translate(0,0);-ms-transform:translate(0,0);transform:translate(0,0)}}.faa-horizontal.animated,.faa-horizontal.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-horizontal{-webkit-animation:horizontal 2s ease infinite;animation:horizontal 2s ease infinite}.faa-horizontal.animated-hover.faa-fast:hover,.faa-horizontal.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-horizontal.faa-fast{-webkit-animation:horizontal 1s ease infinite;animation:horizontal 1s ease infinite}.faa-horizontal.animated-hover.faa-slow:hover,.faa-horizontal.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-horizontal.faa-slow{-webkit-animation:horizontal 3s ease infinite;animation:horizontal 3s ease infinite}@-webkit-keyframes flash{0%,100%,50%{opacity:1}25%,75%{opacity:0}}@keyframes flash{0%,100%,50%{opacity:1}25%,75%{opacity:0}}.faa-flash.animated,.faa-flash.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-flash{-webkit-animation:flash 2s ease infinite;animation:flash 2s ease infinite}.faa-flash.animated-hover.faa-fast:hover,.faa-flash.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-flash.faa-fast{-webkit-animation:flash 1s ease infinite;animation:flash 1s ease infinite}.faa-flash.animated-hover.faa-slow:hover,.faa-flash.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-flash.faa-slow{-webkit-animation:flash 3s ease infinite;animation:flash 3s ease infinite}@-webkit-keyframes bounce{0%,10%,100%,20%,50%,80%{-webkit-transform:translateY(0);transform:translateY(0)}40%,60%{-webkit-transform:translateY(-15px);transform:translateY(-15px)}}@keyframes bounce{0%,10%,100%,20%,50%,80%{-webkit-transform:translateY(0);-ms-transform:translateY(0);transform:translateY(0)}40%,60%{-webkit-transform:translateY(-15px);-ms-transform:translateY(-15px);transform:translateY(-15px)}}.faa-bounce.animated,.faa-bounce.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-bounce{-webkit-animation:bounce 2s ease infinite;animation:bounce 2s ease infinite}.faa-bounce.animated-hover.faa-fast:hover,.faa-bounce.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-bounce.faa-fast{-webkit-animation:bounce 1s ease infinite;animation:bounce 1s ease infinite}.faa-bounce.animated-hover.faa-slow:hover,.faa-bounce.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-bounce.faa-slow{-webkit-animation:bounce 3s ease infinite;animation:bounce 3s ease infinite}@-webkit-keyframes spin{0%{-webkit-transform:rotate(0deg);transform:rotate(0deg)}100%{-webkit-transform:rotate(359deg);transform:rotate(359deg)}}@keyframes spin{0%{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg)}100%{-webkit-transform:rotate(359deg);-ms-transform:rotate(359deg);transform:rotate(359deg)}}.faa-parent.animated-hover:hover>.faa-spin,.faa-spin.animated,.faa-spin.animated-hover:hover{-webkit-animation:spin 1.5s linear infinite;animation:spin 1.5s linear infinite}.faa-parent.animated-hover:hover>.faa-spin.faa-fast,.faa-spin.animated-hover.faa-fast:hover,.faa-spin.animated.faa-fast{-webkit-animation:spin .7s linear infinite;animation:spin .7s linear infinite}.faa-parent.animated-hover:hover>.faa-spin.faa-slow,.faa-spin.animated-hover.faa-slow:hover,.faa-spin.animated.faa-slow{-webkit-animation:spin 2.2s linear infinite;animation:spin 2.2s linear infinite}@-webkit-keyframes float{0%{-webkit-transform:translateY(0);transform:translateY(0)}50%{-webkit-transform:translateY(-6px);transform:translateY(-6px)}100%{-webkit-transform:translateY(0);transform:translateY(0)}}@keyframes float{0%{-webkit-transform:translateY(0);-ms-transform:translateY(0);transform:translateY(0)}50%{-webkit-transform:translateY(-6px);-ms-transform:translateY(-6px);transform:translateY(-6px)}100%{-webkit-transform:translateY(0);-ms-transform:translateY(0);transform:translateY(0)}}.faa-float.animated,.faa-float.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-float{-webkit-animation:float 2s linear infinite;animation:float 2s linear infinite}.faa-float.animated-hover.faa-fast:hover,.faa-float.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-float.faa-fast{-webkit-animation:float 1s linear infinite;animation:float 1s linear infinite}.faa-float.animated-hover.faa-slow:hover,.faa-float.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-float.faa-slow{-webkit-animation:float 3s linear infinite;animation:float 3s linear infinite}@-webkit-keyframes pulse{0%{-webkit-transform:scale(1.1);transform:scale(1.1)}50%{-webkit-transform:scale(0.8);transform:scale(0.8)}100%{-webkit-transform:scale(1.1);transform:scale(1.1)}}@keyframes pulse{0%{-webkit-transform:scale(1.1);-ms-transform:scale(1.1);transform:scale(1.1)}50%{-webkit-transform:scale(0.8);-ms-transform:scale(0.8);transform:scale(0.8)}100%{-webkit-transform:scale(1.1);-ms-transform:scale(1.1);transform:scale(1.1)}}.faa-parent.animated-hover:hover>.faa-pulse,.faa-pulse.animated,.faa-pulse.animated-hover:hover{-webkit-animation:pulse 2s linear infinite;animation:pulse 2s linear infinite}.faa-parent.animated-hover:hover>.faa-pulse.faa-fast,.faa-pulse.animated-hover.faa-fast:hover,.faa-pulse.animated.faa-fast{-webkit-animation:pulse 1s linear infinite;animation:pulse 1s linear infinite}.faa-parent.animated-hover:hover>.faa-pulse.faa-slow,.faa-pulse.animated-hover.faa-slow:hover,.faa-pulse.animated.faa-slow{-webkit-animation:pulse 3s linear infinite;animation:pulse 3s linear infinite}.faa-parent.animated-hover:hover>.faa-shake,.faa-shake.animated,.faa-shake.animated-hover:hover{-webkit-animation:wrench 2.5s ease infinite;animation:wrench 2.5s ease infinite}.faa-parent.animated-hover:hover>.faa-shake.faa-fast,.faa-shake.animated-hover.faa-fast:hover,.faa-shake.animated.faa-fast{-webkit-animation:wrench 1.2s ease infinite;animation:wrench 1.2s ease infinite}.faa-parent.animated-hover:hover>.faa-shake.faa-slow,.faa-shake.animated-hover.faa-slow:hover,.faa-shake.animated.faa-slow{-webkit-animation:wrench 3.7s ease infinite;animation:wrench 3.7s ease infinite}@-webkit-keyframes tada{0%{-webkit-transform:scale(1);transform:scale(1)}10%,20%{-webkit-transform:scale(.9) rotate(-8deg);transform:scale(.9) rotate(-8deg)}30%,50%,70%{-webkit-transform:scale(1.3) rotate(8deg);transform:scale(1.3) rotate(8deg)}40%,60%{-webkit-transform:scale(1.3) rotate(-8deg);transform:scale(1.3) rotate(-8deg)}100%,80%{-webkit-transform:scale(1) rotate(0);transform:scale(1) rotate(0)}}@keyframes tada{0%{-webkit-transform:scale(1);-ms-transform:scale(1);transform:scale(1)}10%,20%{-webkit-transform:scale(.9) rotate(-8deg);-ms-transform:scale(.9) rotate(-8deg);transform:scale(.9) rotate(-8deg)}30%,50%,70%{-webkit-transform:scale(1.3) rotate(8deg);-ms-transform:scale(1.3) rotate(8deg);transform:scale(1.3) rotate(8deg)}40%,60%{-webkit-transform:scale(1.3) rotate(-8deg);-ms-transform:scale(1.3) rotate(-8deg);transform:scale(1.3) rotate(-8deg)}100%,80%{-webkit-transform:scale(1) rotate(0);-ms-transform:scale(1) rotate(0);transform:scale(1) rotate(0)}}.faa-parent.animated-hover:hover>.faa-tada,.faa-tada.animated,.faa-tada.animated-hover:hover{-webkit-animation:tada 2s linear infinite;animation:tada 2s linear infinite}.faa-parent.animated-hover:hover>.faa-tada.faa-fast,.faa-tada.animated-hover.faa-fast:hover,.faa-tada.animated.faa-fast{-webkit-animation:tada 1s linear infinite;animation:tada 1s linear infinite}.faa-parent.animated-hover:hover>.faa-tada.faa-slow,.faa-tada.animated-hover.faa-slow:hover,.faa-tada.animated.faa-slow{-webkit-animation:tada 3s linear infinite;animation:tada 3s linear infinite}@-webkit-keyframes passing{0%{-webkit-transform:translateX(-50%);transform:translateX(-50%);opacity:0}50%{-webkit-transform:translateX(0%);transform:translateX(0%);opacity:1}100%{-webkit-transform:translateX(50%);transform:translateX(50%);opacity:0}}@keyframes passing{0%{-webkit-transform:translateX(-50%);-ms-transform:translateX(-50%);transform:translateX(-50%);opacity:0}50%{-webkit-transform:translateX(0%);-ms-transform:translateX(0%);transform:translateX(0%);opacity:1}100%{-webkit-transform:translateX(50%);-ms-transform:translateX(50%);transform:translateX(50%);opacity:0}}.faa-parent.animated-hover:hover>.faa-passing,.faa-passing.animated,.faa-passing.animated-hover:hover{-webkit-animation:passing 2s linear infinite;animation:passing 2s linear infinite}.faa-parent.animated-hover:hover>.faa-passing.faa-fast,.faa-passing.animated-hover.faa-fast:hover,.faa-passing.animated.faa-fast{-webkit-animation:passing 1s linear infinite;animation:passing 1s linear infinite}.faa-parent.animated-hover:hover>.faa-passing.faa-slow,.faa-passing.animated-hover.faa-slow:hover,.faa-passing.animated.faa-slow{-webkit-animation:passing 3s linear infinite;animation:passing 3s linear infinite}@-webkit-keyframes passing-reverse{0%{-webkit-transform:translateX(50%);transform:translateX(50%);opacity:0}50%{-webkit-transform:translateX(0%);transform:translateX(0%);opacity:1}100%{-webkit-transform:translateX(-50%);transform:translateX(-50%);opacity:0}}@keyframes passing-reverse{0%{-webkit-transform:translateX(50%);-ms-transform:translateX(50%);transform:translateX(50%);opacity:0}50%{-webkit-transform:translateX(0%);-ms-transform:translateX(0%);transform:translateX(0%);opacity:1}100%{-webkit-transform:translateX(-50%);-ms-transform:translateX(-50%);transform:translateX(-50%);opacity:0}}.faa-parent.animated-hover:hover>.faa-passing-reverse,.faa-passing-reverse.animated,.faa-passing-reverse.animated-hover:hover{-webkit-animation:passing-reverse 2s linear infinite;animation:passing-reverse 2s linear infinite}.faa-parent.animated-hover:hover>.faa-passing-reverse.faa-fast,.faa-passing-reverse.animated-hover.faa-fast:hover,.faa-passing-reverse.animated.faa-fast{-webkit-animation:passing-reverse 1s linear infinite;animation:passing-reverse 1s linear infinite}.faa-parent.animated-hover:hover>.faa-passing-reverse.faa-slow,.faa-passing-reverse.animated-hover.faa-slow:hover,.faa-passing-reverse.animated.faa-slow{-webkit-animation:passing-reverse 3s linear infinite;animation:passing-reverse 3s linear infinite}@-webkit-keyframes burst{0%{opacity:.6}50%{-webkit-transform:scale(1.8);transform:scale(1.8);opacity:0}100%{opacity:0}}@keyframes burst{0%{opacity:.6}50%{-webkit-transform:scale(1.8);-ms-transform:scale(1.8);transform:scale(1.8);opacity:0}100%{opacity:0}}.faa-burst.animated,.faa-burst.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-burst{-webkit-animation:burst 2s infinite linear;animation:burst 2s infinite linear}.faa-burst.animated-hover.faa-fast:hover,.faa-burst.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-burst.faa-fast{-webkit-animation:burst 1s infinite linear;animation:burst 1s infinite linear}.faa-burst.animated-hover.faa-slow:hover,.faa-burst.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-burst.faa-slow{-webkit-animation:burst 3s infinite linear;animation:burst 3s infinite linear}@-webkit-keyframes falling{0%{-webkit-transform:translateY(-50%);transform:translateY(-50%);opacity:0}50%{-webkit-transform:translateY(0%);transform:translateY(0%);opacity:1}100%{-webkit-transform:translateY(50%);transform:translateY(50%);opacity:0}}@keyframes falling{0%{-webkit-transform:translateY(-50%);-ms-transform:translateY(-50%);transform:translateY(-50%);opacity:0}50%{-webkit-transform:translateY(0%);-ms-transform:translateY(0%);transform:translateY(0%);opacity:1}100%{-webkit-transform:translateY(50%);-ms-transform:translateY(50%);transform:translateY(50%);opacity:0}}.faa-falling.animated,.faa-falling.animated-hover:hover,.faa-parent.animated-hover:hover>.faa-falling{-webkit-animation:falling 2s linear infinite;animation:falling 2s linear infinite}.faa-falling.animated-hover.faa-fast:hover,.faa-falling.animated.faa-fast,.faa-parent.animated-hover:hover>.faa-falling.faa-fast{-webkit-animation:falling 1s linear infinite;animation:falling 1s linear infinite}.faa-falling.animated-hover.faa-slow:hover,.faa-falling.animated.faa-slow,.faa-parent.animated-hover:hover>.faa-falling.faa-slow{-webkit-animation:falling 3s linear infinite;animation:falling 3s linear infinite}
@media (min-width: 1024px){.topButton{display: none;!important}#goToTop{display: none;!important}}
.back-to-top{
    cursor: pointer;
    position: fixed;
    right: 80px;
    top: -900px;
    z-index: 2;
    width: 70px;
    height: 900px;
    background: url(./img/scroll.png);
    transition: all .5s ease-in-out;
    opacity: 1;
}

最末尾的代码是图片的地址，图片我已经打包了，可以直接下载

最后是js文件，控制滑动返回的效果特效的

 $(function() {
        //scroll 事件适用于所有可滚动的元素和 window 对象（浏览器窗口）。
        $(window).scroll(function() {
                var scroHei = $(window).scrollTop();//滚动的高度
                if (scroHei > 500) {
                   $('.back-to-top').css('top','-200px');
                   // $('.back-to-top').fadeIn();
                } else {                                                
                    $('.back-to-top').css('top','-999px');
                    // $('.back-to-top').fadeOut();
                }
            })
            /*点击返回顶部*/
        $('.back-to-top').click(function() {
            $('body,html').animate({
                scrollTop: 0
            }, 600);
        })
    })

具体就完事了，我这边打包了整个文件，包括图片的素材代码，喜欢的话，直接下载就好了