title: ExtJs is sending bad header on submit on 'Ext.form.field.file'
body: <p>so as mentioned above I am uploading a file through ExtJs using <code>Ext.form.field.file</code>. However, when I do it, it sends the following header <code>Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8</code>. This is causing issues on my back-end (ASP.NET) which thinking that HTML is expected is putting  tags around the JSON causing problems when the response comes back (haven't gotten an answer how to fix this on the ASP.NET side Does anyone have any idea how to modify this header either when sending the request on the ExtJs side or in an ASP.NET controller?</p>