悬浮按钮

<style>
#topBtn {
    position: fixed;
    bottom: 380px;
    right: 50px;
    width: 60px;
    height: 60px;
    line-height: 60px;
    text-align: center;
    color: #FFF;
    z-index: 999;
    background: #FF5722;
    cursor: pointer;
    border-radius: 30px;
    box-shadow: 0px 0px 20px #000;
}
</style>

<script type="text/javascript">
    $(function () {
        $("#topBtn").click(function () {
            $("html,body").animate({scrollTop: $("body").offset().top}, 600);
        });
    });
</script>

 <div id="topBtn">置顶</div>