Index: zen/template.php
===================================================================
RCS file: /cvs/drupal-contrib/contributions/themes/zen/zen/template.php,v
retrieving revision 1.13
diff -u -p -r1.13 template.php
--- zen/template.php	21 Apr 2008 17:03:03 -0000	1.13
+++ zen/template.php	30 Apr 2008 19:51:53 -0000
@@ -339,10 +339,12 @@ function phptemplate_preprocess_block(&$
 /**
  * Converts a string to a suitable html ID attribute.
  *
- * - Preceeds initial numeric with 'n' character.
+ * http://www.w3.org/TR/html4/struct/global.html#h-7.5.2 specifies what makes a
+ * valid ID attribute in HTML. This function:
+ *
+ * - Ensure an ID starts with an alpha character by optionally adding an 'n'.
  * - Replaces any character except A-Z, numbers, and underscores with dashes.
  * - Converts entire string to lowercase.
- * - Works for classes too!
  *
  * @param $string
  *   The string
@@ -350,11 +352,13 @@ function phptemplate_preprocess_block(&$
  *   The converted string
  */
 function zen_id_safe($string) {
-  if (is_numeric($string{0})) {
-    // If the first character is numeric, add 'n' in front
+  // Replace with dashes anything that isn't A-Z, numbers, dashes, or underscores.
+  $string = strtolower(preg_replace('/[^a-zA-Z0-9_-]+/', '-', $string));
+  // If the first character is not a-z, add 'n' in front.
+  if (!ctype_lower($string{0})) { // Don't use ctype_alpha since its locale aware.
     $string = 'n'. $string;
   }
-  return strtolower(preg_replace('/[^a-zA-Z0-9_-]+/', '-', $string));
+  return $string;
 }
 
 /**