Index: misc/ajax.js
===================================================================
RCS file: /cvs/drupal/drupal/misc/ajax.js,v
retrieving revision 1.26
diff -u -p -r1.26 ajax.js
--- misc/ajax.js	23 Oct 2010 15:46:43 -0000	1.26
+++ misc/ajax.js	24 Oct 2010 15:15:16 -0000
@@ -280,7 +280,7 @@ Drupal.ajax.prototype.success = function
   if (this.progress.object) {
     this.progress.object.stopMonitoring();
   }
-  $(this.element).removeClass('progress-disabled').attr('disabled', false);
+  $(this.element).removeClass('progress-disabled').removeAttr('disabled');
 
   Drupal.freezeHeight();
 
@@ -348,7 +348,7 @@ Drupal.ajax.prototype.error = function (
   // Undo hide.
   $(this.wrapper).show();
   // Re-enable the element.
-  $(this.element).removeClass('progress-disabled').attr('disabled', false);
+  $(this.element).removeClass('progress-disabled').removeAttr('disabled');
   // Reattach behaviors, if they were detached in beforeSerialize().
   if (this.form) {
     var settings = response.settings || this.settings || Drupal.settings;