js创建3个节点的目录树

<script type="text/javascript">
    var div = document.createElement("div");
    var a = document.createElement("a");
    var span =  document.createElement("span");
    a.href = "http://www.baidu.com";
    span.innerHTML = "baidu";
    a.appendChild(span);
    div.appendChild(a);
    document.body.appendChild(div);
</script>


//结果
<div>
　　<a href="http://www.baidu.com"><span>baidu</span></a>
</div>