diff --git a/core/misc/ajax.es6.js b/core/misc/ajax.es6.js
index 8a99a544fe..4d849096e0 100644
--- a/core/misc/ajax.es6.js
+++ b/core/misc/ajax.es6.js
@@ -481,7 +481,7 @@
       beforeSubmit(formValues, elementSettings, options) {
         ajax.ajaxing = true;
         const continueSubmit = ajax.beforeSubmit(formValues, elementSettings, options);
-        if (!continueSubmit) {
+        if (continueSubmit === false) {
           ajax.ajaxing = false;
         }
         return continueSubmit;
@@ -489,7 +489,7 @@
       beforeSend(xmlhttprequest, options) {
         ajax.ajaxing = true;
         const continueSend = ajax.beforeSend(xmlhttprequest, options);
-        if (!continueSend) {
+        if (continueSend === false) {
           ajax.ajaxing = false;
         }
         return continueSend;
diff --git a/core/misc/ajax.js b/core/misc/ajax.js
index a4f877131c..e036b97123 100644
--- a/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -206,7 +206,7 @@ function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr
       beforeSubmit: function beforeSubmit(formValues, elementSettings, options) {
         ajax.ajaxing = true;
         var continueSubmit = ajax.beforeSubmit(formValues, elementSettings, options);
-        if (!continueSubmit) {
+        if (continueSubmit === false) {
           ajax.ajaxing = false;
         }
         return continueSubmit;
@@ -214,7 +214,7 @@ function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr
       beforeSend: function beforeSend(xmlhttprequest, options) {
         ajax.ajaxing = true;
         var continueSend = ajax.beforeSend(xmlhttprequest, options);
-        if (!continueSend) {
+        if (continueSend === false) {
           ajax.ajaxing = false;
         }
         return continueSend;