diff --git a/js/ajax.js b/js/ajax.js
index ece1038cc6..561b61861c 100644
--- a/js/ajax.js
+++ b/js/ajax.js
@@ -405,7 +405,9 @@ AJAX.registerOnload('functions.js', function () {
     // Registering the onload event for functions.js
     // ensures that it will be fired for all pages
     $('form').not('.ajax').not('.disableAjax').each(function () {
-        $(this).data('onsubmit', this.onsubmit).attr('onsubmit', '');
+        if ($(this).attr('onsubmit')) {
+            $(this).data('onsubmit', this.onsubmit).attr('onsubmit', '');
+        }
     });
 });