diff --git a/js/recaptcha.invisible.js b/js/recaptcha.invisible.js
index da7e4ce..8093b6f 100644
--- a/js/recaptcha.invisible.js
+++ b/js/recaptcha.invisible.js
@@ -45,25 +45,33 @@ function recaptchaOnInvisibleSubmit() {
   Drupal.behaviors.invisibleRecaptcha = {
     attach: function (context) {
       if (Drupal.hasOwnProperty('Ajax')) {
+        var originalBeforeSubmit = Drupal.Ajax.prototype.beforeSubmit;
         Drupal.Ajax.prototype.beforeSubmit = function (form_values, element, options) {
-          if ($(this.element).is(clickedSubmit) && grecaptcha.getResponse().length === 0) {
+          if (this.event === 'mousedown' && $(this.element).data('recaptcha-submit') && grecaptcha.getResponse().length === 0) {
+            clickedSubmit = this.element;
             options.needsRevalidate = true;
             this.progress.type = 'none';
             clickedSubmitAjaxEvent = this.event;
           }
+
+          originalBeforeSubmit.apply(this, arguments);
         };
 
-        $(document).ajaxSend(function (event, jqxhr, settings) {
-          if (settings.needsRevalidate) {
-            jqxhr.abort();
-            $(clickedSubmit).prop('disabled', false);
-          }
-        });
+        if (!$(document).data('invisible-recaptcha-ajax-send-processed')) {
+          $(document).ajaxSend(function (event, jqxhr, settings) {
+            if (settings.needsRevalidate) {
+              jqxhr.abort();
+              $(clickedSubmit).prop('disabled', false);
+            }
+          });
+
+          $(document).data('invisible-recaptcha-ajax-send-processed', true);
+        }
       }
       $('form', context).each(function () {
         var $form = $(this);
         if ($form.find('.g-recaptcha[data-size="invisible"]').length) {
-          $form.find(':submit').on({
+          $form.find(':submit').data('recaptcha-submit', true).on({
             'mousedown.recaptcha': function (e) {
               preventFormSubmit(this, e);
             },
@@ -83,10 +91,21 @@ function recaptchaOnInvisibleSubmit() {
       function preventFormSubmit(elem, event) {
         if (grecaptcha.getResponse().length === 0) {
           // We need validate form, to avoid prevention of html5 validation.
-          if ($(elem).closest('form')[0].checkValidity()) {
-            event.preventDefault();
-            event.stopPropagation();
-            clickedSubmitEvent = event.type;
+          var form = $(elem).closest('form')[0];
+          if (form && typeof form.checkValidity === 'function') {
+            if (form.checkValidity()) {
+              event.preventDefault();
+              event.stopPropagation();
+              clickedSubmitEvent = event.type;
+              validateInvisibleCaptcha(elem);
+            }
+            else {
+              if (typeof form.reportValidity === 'function') {
+                form.reportValidity();
+              }
+            }
+          }
+          else {
             validateInvisibleCaptcha(elem);
           }
         }