返回页首

<div style="background-color: #CCCCCC;width: 70px;position: fixed;bottom: 5px;right: 5px;font-size: 0;line-height: 0;z-index: 100;">
    <a href="#" id="btn-scroll-up" class="btn-scroll-up btn btn-sm btn-inverse display">返回顶部</a>
</div>