Add active class on 'show all' filter list

The CMS Questions
3

Thx but i can’t get it to work. What am i missing?

<ul class="tags">
  <li <?= param('tag') === '' ? 'class="active"' : '' ?>><a href="<?= $page->url() ?>">all</a></li>
  <?php foreach($tags as $tag): ?>
    <li <?= param('tag') == $tag ? 'class="active"' : '' ?>>
      <a href="<?= url($page->url(), ['params' => ['tag' => $tag]]) ?>">
        <?= html($tag) ?>
      </a>
    </li>
  <?php endforeach ?>
</ul>