易優CMS每隔N行輸出內容判斷

{eyou:arclist typeid='文件ID' limit='0,10' mod='每隔幾條'}
{eyou:eq name='mod' value='0'}<li></li>{/eyou:eq}
<a href='{$field.arcurl}'>{$field.title}</a>
{/eyou:arclist}