diff --git a/admin_menu.js b/admin_menu.js
index 65911cf..f8c730a 100644
--- a/admin_menu.js
+++ b/admin_menu.js
@@ -125,7 +125,7 @@ Drupal.admin.getCache = function (hash, onSuccess) {
       Drupal.admin.hashes.hash = status;
     }
   });
-}
+};
 
 /**
  * @defgroup admin_behaviors Administration behaviors.
@@ -172,7 +172,7 @@ Drupal.admin.behaviors.replacements = function (context, settings, $adminMenu) {
   for (var item in settings.admin_menu.replacements) {
     $(item, $adminMenu).html(settings.admin_menu.replacements[item]);
   }
-}
+};
 
 /**
  * Inject destination query strings for current page.
@@ -183,7 +183,7 @@ Drupal.admin.behaviors.destination = function (context, settings, $adminMenu) {
       this.search += (!this.search.length ? '?' : '&') + Drupal.settings.admin_menu.destination;
     });
   }
-}
+};
 
 /**
  * Apply JavaScript-based hovering behaviors.
diff --git a/admin_menu.module b/admin_menu.module
index d05e987..d1d9f4a 100644
--- a/admin_menu.module
+++ b/admin_menu.module
@@ -132,8 +132,11 @@ function admin_menu_init() {
   if ($user->uid == 1) {
     drupal_add_css($path . '/admin_menu.uid1.css');
   }
-  // Performance: Defer execution.
-  drupal_add_js($path . '/admin_menu.js', array('defer' => TRUE));
+  // Previous versions used the 'defer' attribute to increase browser rendering
+  // performance. At least starting with Firefox 3.6, deferred .js files are
+  // loaded, but Drupal.behaviors are not contained in the DOM when drupal.js
+  // executes Drupal.attachBehaviors().
+  drupal_add_js($path . '/admin_menu.js');
 
   // Destination query strings are applied via JS.
   $settings['destination'] = drupal_http_build_query(drupal_get_destination());