[jQuery] ajaxForm - how to give a failure message

[BigLob]

Hi there,

I'm trying to make a form that has both browser and server side
validation.
I'm using the validate plugin for browser side and thats working fine.
I'm using the form plugin for server side.  I'm using ajaxForm to test
if the form was submitted and then display a thankyou message.
My question is how do I display an error message if the form did not
validatae server side?

Here's my code so far:

$("#myForm").validate({
        success: "valid",
        submitHandler: function(form) {
        // bind 'myForm' and provide a simple callback function
        $('#myForm').ajaxForm(function() {
              alert("Thank you for your comment!");
                });

         });
}

What do I need to add to let the user know they didn't fill out the
form correctly?

Thanks in Advance