匿名Basic Tree
Click the arrow on the left to expand or collapse nodes.
示例：
代码：
<div class="easyui-panel" style="padding:5px">
<ul class="easyui-tree">
<li>
<span>My Documents</span>
<ul>
<li data-options="state:'closed'">
<span>Photos</span>
<ul>
<li>
<span>Friend</span>
</li>
<li>
<span>Wife</span>
</li>
<li>
<span>Company</span>
</li>
</ul>
</li>
<li>
<span>Program Files</span>
<ul>
<li>Intel</li>
<li>Java</li>
<li>Microsoft Office</li>
<li>Games</li>
</ul>
</li>
<li>index.html</li>
<li>about.html</li>
<li>welcome.html</li>
</ul>
</li>
</ul>
</div>