{eyou:channel type="top" row="60" id="field" currentstyle="active"}
<li class="nav-item"><a href="{$field.typeurl}" target="_blank" class="nav-link {$field.currentstyle}{eyou:notempty name="$field.children"}active{/eyou:notempty}">{$field.typename}</a>
{eyou:notempty name="$field.children"}
<div class="dropdown-menu">
{eyou:channel name="$field.children" row="100" id="field2"}
<a href="{$field2.typeurl}"> <span>{$field2.typename}</span></a>
{/eyou:channel}
</div>
{/eyou:notempty}
</li>
{/eyou:channel}