...
$('#testForm') .validate({ rules: { 'email': { required: true, remote: { param: { url: "some_ajax_validation_url", type: 'post', data: { email: function() { return $('[name="email"]').val(); }, userid: function() { return $('[name="userid"]').val(); } } }, depends: function(element){ // compare to original value and run remote check if different return ($(element).val() !== $('#originalemail').val()); } } } } });