diff -u b/core/modules/views/js/exposed-form-ajax.js b/core/modules/views/js/exposed-form-ajax.js
--- b/core/modules/views/js/exposed-form-ajax.js
+++ b/core/modules/views/js/exposed-form-ajax.js
@@ -2,7 +2,9 @@
  * @file
  * Handles Views' exposed form AJAX data submission.
  */
+
 (function ($) {
+  'use strict';
 
   /*
    * Gets Form build info from settings and adds it to ajax data.
@@ -10,14 +12,16 @@
    * @see views_exposed_form_ajax_enable().
    */
   Drupal.behaviors.ViewsExposedFormAjax = {
-    attach: function(context, settings) {
-      for (var ajaxObject in Drupal.ajax.instances) {
-        for(var name in drupalSettings.ViewsExposedFormInfo) {
-          if (Drupal.ajax.instances[ajaxObject].options && Drupal.ajax.instances[ajaxObject].options.data._triggering_element_name == name) {
-            jQuery.extend(Drupal.ajax.instances[ajaxObject].options.data, drupalSettings.ViewsExposedFormInfo[name]);
+    attach: function (context, settings) {
+      Drupal.ajax.instances.forEach(function (instance, key) {
+        for (var name in drupalSettings.ViewsExposedFormInfo) {
+          if (drupalSettings.ViewsExposedFormInfo.hasOwnProperty(name)) {
+            if (instance.options && instance.options.data._triggering_element_name === name) {
+              jQuery.extend(Drupal.ajax.instances[key].options.data, drupalSettings.ViewsExposedFormInfo[name]);
+            }
           }
-        }
-      }
+        };
+      });
     }
   };
 
diff -u b/core/modules/views/views.module b/core/modules/views/views.module
--- b/core/modules/views/views.module
+++ b/core/modules/views/views.module
@@ -663,7 +663,7 @@
  *
  * @return array
  */
-function views_exposed_form_ajax_enable(&$form, FormStateInterface $form_state) {
+function views_exposed_form_ajax_enable($form, FormStateInterface $form_state) {
   // In order for Ajax to work, we need the form build info. Here we
   // check if #ajax has been added to any form elements, and if so,
   // pass this info as settings via Javascript, which get attached to