I have a Django site where one page is doing an AJAX-based file upload (using Valum's file uploader) that returns some info back via JSON. The way the JSON is returned by Django is...
return HttpResponse( json.dumps( info ), mimetype="application/json" )
When trying the page in Firefox, Chrome, and Safari I get the appropriate behavior of the file uploader marking the upload as complete and the data being inserted into a table on the page.
When testing in IE8 I get incorrect behavior after Django sends the JSON back: a download dialog comes up--which is the JSON text if you save it--and the file uploader continues to think the file is uploading since it has received no response from the server. IE must be seeing the response and interpreting it as a download rather than passing it to the page's javscript. Note that I've tried changing the mime to application/javascript and this appeared to make no difference. Anyone got a fix?