现在是每一个导航都增加了这个class类名
{eyou:channel type="top" id="field" currentstyle="active"}
<li class="allchanpin allabout_us">
<a class="chanpin about_us {$field.currentstyle}" href="{$field.typeurl}">{$field.typename}</a>
<div class="about_us_list">
<ul class="tipclass">
{eyou:channel name="$field.children" id="field2"}
<li><a href="{$field2.typeurl}">{$field2.typename}</a></li>
{/eyou:channel}
</ul>
</div>
</li>
{/eyou:channel}