of radio buttons, checkboxes and file.
        var type = element.type.toLowerCase();

        // Don't do anything for unchecked checkboxes/radio buttons.
        // Don't do anything for file, since that requires a different request.
        if (((type === 'checkbox' || type === 'radio') && !element.checked) ||
            type === 'file') {
          return [];
        }
        return [element.value];
      },

      _createHiddenElement: function(name, value) {
        var input = document.createElemen