How to enable CORS on Firefox?

Question

Can somebody please tell me how I allow CORS on firefox? I easily managed it on Chrome and IE, but I am totally failing at it with Firefox. I edited the following about:conf

Answer 1

This Firefox add-on may work for you:

https://addons.mozilla.org/en-US/firefox/addon/cors-everywhere/

It can toggle CORS on and off for development purposes.