Well this is embarrassing. Issue wasn't the ajax or web2py, it was a typo in controller.
For future reference, The reason why web2py error came up as above (None post vars) was that I was double clicking on the failed network request in the chrome devtool and it was opening controller/upload_file, which obviously will not get any vars. Everything's good now. -- Resources: - http://web2py.com - http://web2py.com/book (Documentation) - http://github.com/web2py/web2py (Source code) - https://code.google.com/p/web2py/issues/list (Report Issues) --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.

