thinkphp 模板的volist嵌套循环

1    <ul class="smenu">
2    <volist name="parent_menu" id="pm">
3        <li onmouseout="liMouseOut()" onmouseover="setLiMouseOver()" class="s_li{$pm.id|index_menu_class=###,$pm.sort}" id="s_{$pm.id}">
4            <span class="zhix"></span>
5            <span class="s_li_l"></span>
6            <span class="s_li_m">
7            <volist name="child_menu" id="cm">
8                <eq name="cm.pid" value="$pm.id">
9                <a href="{$cm.link}" target="{$cm.target}">● {$cm.title}</a>
10                </eq>
11            </volist>
12            </span>
13            <span class="s_li_r"></span>
14        </li>
15    </volist>
16    </ul>