> I have a simple file upload form. It works exactly as expected
> without javascript. It *almost* works as expected when I convert it
> to an ajax form, with something like form.ajaxSubmit(options). My
> options contain a dataType definition, {'dataType' : 'json'}. I
> believe that this directly relates to the HTTP Accept header and lets
> my server know the type of data that I'm expecting to get back. If I
> don't select a file to upload and hit submit then the Accept header is
> populated correctly ("application/json, text/javascript, */*"). If I
> do select a file to upload and hit submit then the Accept header
> ignores my dataType and appears to default to the browser default
> (something like "text/html,application/xhtml+xml,application/
> xml;q=0.9,*/*;q=0.8"). In practice, this means that although the file
> is uploaded correctly, I'm unable to determine the the type of
> response required from the server (in Rails I can't use respond_to to
> detect a request for a js response). I'm wondering whether this is by
> design or whether something's wrong here.
File uploads don't use ajax, the form plugin only makes it appear that
way. A true browser submit takes place when uploading a file.
