Ticket #34033: 34033-3.diff

src/wp-content/themes/twentythirteen/js/functions.js

@@ -34 +34 @@
          * Enables menu toggle for small screens.
          */
         ( function() {
-                if ( ! nav || ! button ) {
+                if ( ! nav.length || ! button.length ) {
                         return;
                 }
 
                 // Hide button if menu is missing or empty.
-                if ( ! menu || ! menu.children().length ) {
+                if ( ! menu.length || ! menu.children().length ) {
                         button.hide();
                         return;
                 }