title: JQuery validation plugin and custom rule
body: <p>I'm using the jquery.validation plugin in my web app.
  I have this general code for form validation:</p>
  
  <pre><code>$('form[data-toggle="validator"]').each(function () {
              $(this).validate({
                  errorClass: "help-block error",
                  errorElement: "div",
                  focusCleanup: false,
                  focusInvalid: false,
                  submitHandler: function(form){
                      $("[type=submit]",form).prop("disabled",true);
                      form.submit();
                  }
              });
           });
  </code></pre>
  
  <p>When I need the validation I just set the data-toggle attribute to the form.</p>
  
  <p>In a particular case I would like to add a custom rule, not for a single input element, but for all the form.
  I would like to add it at runtime, is it possibile?</p>