(function ($) {

  Drupal.behaviors.formSingleSubmit = {
    attach: function () {
            function onFormSubmit (e) {
              if (e.isDefaultPrevented()) {
                // Don't act on form submissions that have been prevented by other JS.
                return;
              }
              var $form = $(e.currentTarget);
              var formValues = $form.serialize();
              var previousValues = $form.attr('data-drupal-form-submit-last');
              if (previousValues === formValues) {
                e.preventDefault();
              }
              else {
                $form.attr('data-drupal-form-submit-last', formValues);
              }
            }

            $('body').once('form-single-submit')
              .delegate('form:not([method~="GET"])', 'submit.singleSubmit', onFormSubmit);

    }
  };
})(jQuery);