{assign var="level" value=1}
{function name=categories_tree}
{if $categories}
<ul id="nav" ul-level='{$level}' {if $level == 1}class='top_ul'{else}class='sub_ul ul_level_{$level}'{/if}>
{foreach $categories as $c}
{if $c->visible}
<li class='level_{$level} {if in_array($category->id, $c->children)}active{/if}'>
<a href="catalog/{$c->url}" data-category="{$c->id}">{$c->name|escape}</a>
{categories_tree categories=$c->subcategories level=$level+1}
</li>
{/if}
{/foreach}
</ul>
{/if}
{/function}
{categories_tree categories