diff --git a/includes/alter.inc b/includes/alter.inc
index c4a9677..ed9ab52 100644
--- a/includes/alter.inc
+++ b/includes/alter.inc
@@ -323,7 +323,7 @@ function bootstrap_js_alter(&$js) {
   if (empty($js['misc/jquery.once.js'])) {
     $jquery_once = drupal_get_library('system', 'jquery.once');
     $js['misc/jquery.once.js'] = $jquery_once['js']['misc/jquery.once.js'];
-    $js['misc/jquery.once.js'] += drupal_js_defaults('misc/jquery.once.js');
+    $js['misc/jquery.once.js'] = array_replace(drupal_js_defaults('misc/jquery.once.js'), $js['misc/jquery.once.js']);
   }
 
   // Always add bootstrap.js last.