eyoucms底部导航判断有子栏目调用子栏目，无子栏目调用当前栏目描述，代码如下：
{eyou:channel row='4' type='top'}
<div class="main">
{eyou:notempty name="$field.children"}
<a href="{$field.typeurl}" class="dt">{$field.typename}</a>
{eyou:else /}
<a href="{$field.typeurl}" class="dt">{$field.typename}</a>
<a href="{$field.typeurl}"><span>{$field.seo_description|html_msubstr=###,0,250}</span></a>
{/eyou:notempty}
{eyou:notempty name="$field.children"}
{eyou:channel name="$field.children" row="5" id="field2"}
<a href="{$field2.typeurl}" class="dd">{$field2.typename}</a>
{/eyou:channel}
{/eyou:notempty}
</div>
{/eyou:channel}