[jQuery] Updating input values before the submit.

[Jesse R.]

I have the following html code:

<form id="googleCheckout" action="https://sandbox.google.com/checkout/
cws/v2/Merchant/747474/checkout" method="post">
<input type="hidden" name="cart" value="somevalue" />
<input type="hidden" name="signature" value="anothervalue" />
<input type="image" name="Google Checkout" alt="Fast checkout through
Google"
src="https://sandbox.google.com/checkout/buttons/checkout.gif?
merchant_id=747474&amp;w=160&amp;h=43&amp;style=WHITE&amp;variant=TEXT&amp;loc=en_US"
height="43" width="160" />
</form>

I want to dynamically load those values with a json request
immediately before the submit, but not any sooner.  I tried doing the
following code:


jQuery("#googleCheckout").submit(function() {
                         jQuery.ajax({
                           type: "POST",
                           dataType: "json",
                           url: "/json-checkout",
                           error: function(){return false;},
                           success: function(json){
                            jQuery("input:first").attr({
                                        value: json.gec
                                        });
                                jQuery("input:eq(1)").attr({
                                        value: json.ges
                                        });
                                return true;
                        }
                           });
                         });

However, the ajax request fails according to Firebug and the submit
contains the old data.  The requested URL is 
http://www.blueskyvineyard.com/json-checkout.
Any suggestions would be greatly appreciated!