$(document).ready(function()

 {

$('form').validate();

 $('input[required]').each(function () {

        $(this).rules("add", {

            required: true

        });

  });

  });

  </script>

  </head>

<form id="form">

            <input id="txt_field2" name="txt_field2" type="text" class="required"/>

            <input id="wh-submit-button" type="submit" value="submit" />

</form>