锚点-楼层效果
<div id="test"></div>
<a href="#test">回到首页</a>
//将样式修改一下就可以用了
<div id="box1"></div>
<div id="box2"></div>
<div id="box3"></div>
<div id="box4"></div>
<a href="#box1">F1</a>
<a href="#box2">F2</a>
<a href="#box3">F3</a>
<a href="#box4">F4</a>