[jQuery] Validating Submit from Image Button (Validate)

[Dakuwan]

I am having the following issue, when I try using an image to post I
cannot get the validation to run.  When I click the button the form
submits and nothing is checked.  I've been searching all over the web
and cant find any help.  One way of coding doesnt work and the other
does.  I have included both below.  I'd really appreciate the help.

This code doesnt work:
$().ready(function() {

        var container = $('div.container');

        var validator = $("#CustForm").validate({
                errorContainer: container,
                wrapper: 'li',
                meta: "validate",
                rules: {
                        credit_card: {
                                required: function(element) {
                                        return $("#payment_type").val() == 
'credit'
                                        }
                                }
                        card_month: {
                                required: function(element) {
                                        return $("#payment_type").val() == 
'credit'
                                        }
                                }
                        card_year: {
                                required: function(element) {
                                        return $("#payment_type").val() == 
'credit'
                                        }
                                }
                        card_number_ccard: {
                                required: function(element) {
                                        return $("#payment_type").val() == 
'credit'
                                        }
                                }

                }
        });

        $('#CustForm input:image#nextButton').click(function() {
         return $('CustForm').valid();
        });

});

If I do this however it does work.  I have to have the rules run
because based on the payment type selected certain fields become
required.

$().ready(function() {

        var container = $('div.container');

        var validator = $("#CustForm").validate();

        $('#CustForm input:image#nextButton').click(function() {
         return $('CustForm').valid();
        });

});

This is my button code:
<cfinput type="image" src="nextstep.gif" value="submit"
name="nextButton" id="nextButton" border=0 class="submit">

Thanks for the help.