If you are using a Zen-based theme you can use the Zen function zen_id_safe
replace line
$id = preg_replace("/[^a-zA-Z0-9]/", "", strip_tags($link));
with
$id = zen_id_safe(strip_tags($link));

So, I need to add a unique class to each secondary menu ul. If that doesn't make sense, here's an example

I have one menu. My menu has 4 primary items and about 6 secondary items under each primary.
My page design shows all primary items and the expanded secondary menu for that section.

I need to be able to style (through css) the secondary menu items differently for each section. So for sectionA, the secondary menu has a margin of 100px. For sectionB, the secondary menu has a margin of 300px and on...

There is currently only an id="secondary-links" on my ul tag. I need to add a unique class or id for each secondary ul based on the primary link.

Using the genesis theme starter if that makes a difference. Help appreciated!

I've added it to my template file, but my menus don't change at all. I don't get it! Am I doing something wrong- this is so frustrating!

EDIT: all good- I had to flush my cache and run cron.

I'm not having any luck with this in Zen in Drupal 6.19. I have also tried in Garland, and its not working there. I have of course flushed all caches and run cron each time. Is there something I could be doing wrong when adding this code to template.php? It's not that the ID function simply isn't working because I'm not seeing any change at all in the menu items (ie. I'm not seeing id="").

How it can be used only for Primary links?

Exactly what I need! Work perfectly!

never mind

Menu items IDs seem to change on me.
Is this indicative of some type of menu failure or are they not a stable thing to rely on for styling icons etc?

menu_attribute module can be used here to give unique id to each menu item.

Hi,

I have done something similar to the OP to create custom menu items in my Drupal 6 menu. I required quite an extensive customised html/css output in order style the menu in a reasonably complex way. I have included the code below in case it is of value to anyone else.

What I now need to achieve is to allow the customised menu_item code to distinguish which menu the menu_item is from, so that the output is different for the main navigation and my custom menus. I expect I could achieve this by using an if statement in the function phptemplate_menu_item e.g.

function phptemplate_menu_item (...){
if ($menu_name == 'primary-links')
{DO ABC}
else
{DO XYZ}
}

However I don't think the $menu_name is currently being passed to the menu_item? So the first thing I may need to do is work out how to pass the menu_name to the phptemplate_menu_item. I been searching for quite a while for possible solutions to this, so any input or areas I should read up on would be appreciated. Thanks!

I have included my current code below for anyone who may benefit from it:

function phptemplate_menu_item($link, $has_children, $menu_name, $menu = '', $in_active_trail = FALSE, $extra_class = NULL) {
  
  $class = ($menu ? 'no_wrap' : ($has_children ? 'collapsed' : 'li_wrap'));
  if (!empty($extra_class)) {
    $class .= ' '. $extra_class;
  }
  if ($in_active_trail) {
    $class .= ' active-trail';
  }
  if (!empty($link)) {
	/* The following section gives the list items unique classes based on their link text - note how spaces and sepcial chars are removed */
	// remove all HTML tags and make everything lowercase
	$css_id = strtolower(strip_tags($link));
	// remove colons and anything past colons
	if (strpos($css_id, ':')) $css_id = substr ($css_id, 0, strpos($css_id, ':'));
	// Preserve alphanumerics, everything else goes away
	$pattern = '/[^a-z]+/ ';
	$css_id = preg_replace($pattern, '', $css_id);
	$class .= ' '. $css_id;
	}
	// the following code returns the menu item formatted in a different fashion depending on the class of the item. The first one is for items with a class of none - ie the space li at end of menu
	if (strstr($class, 'none')) {
		  return '<li class="'. $class . $menu_name . ' main"></span></span></li>';
	}
  	if (strstr($class, 'li_wrap')) {
		  return '<li class="'. $class . $menu_name . ' main"><span class="wrapped">'. $link . $menu ."<span class='indicator'></span></li>\n";
	}
	if (strstr($class, 'no_wrap')) {
		  return '<li class="'. $class . ' main">'. $link ."<span class='indicator'></span><span class='menu_box'><span class='menu_box_inner'>". $menu ."</span></span></li>\n";
	}
	
}

This code was written when D8 was at alpha2 so I can't 100% guarantee this won't change. I also added a bit to reset the static variable when printing the last link, so that the class starts at 1 for each variable.

use Drupal\Core\Template\Attribute; 

function MYTHEME_menu_link($variables) {
  
  $element = $variables['element'];

  static $item_id = 0;
  $element['#attributes']['class'][] = 'menu-item-custom-id' . (++$item_id);
  $sub_menu = $element['#below'] ? drupal_render($element['#below']) : '';

  $output = l($element['#title'], $element['#href'], $element['#localized_options']);
  if(in_array('last', $element['#attributes']['class'])) {
     $item_id = 0; 
  } 

  return '<li' . new Attribute($element['#attributes']) . '>' . $output . $sub_menu . "</li>\n";
 
}