[jQuery] jquery form plugin problem

Hi,

I'm trying to use the form plugin from malsup.org to submit a form
with ajax, but it does not seem to work with options.

This works:

$("#loginform").ajaxSubmit(function(obj,
statusText) {
alert(obj);
});

This does not work (nothing happens):

$("#loginform").ajaxSubmit({
dataType: "json",
success: function(obj, statusText) {
alert(obj);
}
});

Oh, and by the way. Is there any way to get access to the request in
the 'success' function - to obtain status codes, content-type header
etc.?

Thanks,

-dennis