Update: check Tertiary links / 2: tree workaround before this. That’s a wiser solution in many cases.

Tested on:

• Drupal 5.x
• Zen subtheme

If you use primary and secondary links in distinct blocks/area of a page, you can add the ability to browse the third navigation level. Just hack your page.tpl.php.


<div id="secondary"> <?php
#display tertiary links menu on 2nd level
$tertiary_links=menu_primary_links(3, variable_get('menu_primary_menu', 0) );
#display secondary links menu on 1st level
if($my_secondary_links):?>
<?php
print theme('links', $my_secondary_links, array('class' => 'links tertiary-links'));
?>
elseif ($secondary_links): ?>
<?php
print theme('links', $secondary_links);
?>
</div> <!-- /#secondary -->
<?php endif; ?>

See also:

• Tertiary menu in Drupal A very useful howto (I saw this trick here)
• Secondary link and third level Topic on drupal.org

Tested on: Zen theme, Drupal 5.7

1. Copy function theme_links from includes/themes.inc
2. Paste it into your template.php
3. Rename it in theme_primarylinks (or anything you want)
4. In your page.tpl.php, change
   1. print theme(‘links’, $primary_links);
   2. to print theme(‘primarylinks’, $primary_links);
5. Apply some changes to theme_primarylinks to customize your primary links.

According to theme manual, for any first argument passed to theme function a theme_functionname function is called.