If the XHR error suggests that the xhr.status is 0 (i.e., it didn't

If the XHR error suggests that the xhr.status is 0 (i.e., it didn't
receive an XHR object as expected), threat it as a success like HTTP
20x or 30x because the notice most likely went through. jquery.form.js
(for file uploads) and meteor.js both use an iframe and they (somehow)
appear to be in conflict. Notice always goes through, however,
xhr.status is 0. Further investigation is needed.