Need help — weird jQuery bugs

Right now, with the ajax uncommented, $('.export').click, etc... works. The default is prevented, $('#exportform').show(); works, and the modal appears.

Then, when you uncomment this:

// $.ajax({
//     type: "POST",
//     url: $url,
//     data: $(this).serialize();
//   }).done(function() {
//     $('#exportform').hide();
//   });

...before you even get to submitting the modal, or it even appearing, you're redirected to the root ('/').

Any thoughts?