upgrade 2.1.2 to 2.1.3 ajax error

[eluser]Narf[/eluser]
My guess is that your AJAX request is sent via the POST method, but doesn't really send any POST fields. One of the changes in CI 2.1.3 is to set a CSRF cookie only on non-POST requests, while in 2.1.2 it used to set it if there was simply no POST data sent in the request.