jQuery AJAX fails to work (OPTIONS pre-flight request made) when headers are specified

Question

The AJAX request works fine, but the moment I add a header via beforeSend or headers, an OPTIONS pre-flight request is made and the GET request is aborted.

Answer 1

Solved. Thanks @JasonP for pointers. Changed Server Response Headers from

Access-Control-Allow-Headers:*

to specific ones

Access-Control-Allow-Headers: Content-Type, Accept, X-Requested-With, Session

and now it works!