UPDATE:
Confirmed: This has been fixed on the iOS 8.0.2 update.
Using PUT/POST to upload file(s) over HTTP seems to get stuc
Update: Apple released iOS 8.0.2 yesterday and has fixed the upload bug.
File upload are broken in iOS 8.0. All files uploaded in Mobile Safari return 0-sized [1].
Hopefully this gets fixed by Apple in the next release. It seems like it is not affecting home screen webapps though:
File uploads are broken!! Every file upload is not working, you can select a file or take a picture and after that JavaScript will not get any data, as well as the server on a POST upload through HTML or XMLHttpRequest upload. The problem doesn’t seem to apply for home screen webapps.
Source: http://www.mobilexweb.com/blog/safari-ios8-iphone6-web-developers-designers
[1] http://blog.fineuploader.com/2014/09/10/ios8-presents-serious-issues-that-prevent-file-uploading/