Do you see a response in the browser console of Iceweasel 17 / Firefox 23 when you run this playground sample?
http://tinyurl.com/oaky63o
Within this sample I'm using jsontest.com [1] and it's echo service [2] which responds with the Access-Control-Allow-Origin header (the value is *), so hopefully you should be able to verify that this code snippet also runs within your aforementioned browser versions.
I'm assuming that you are using GET and sending no data, so please correct me here if that's wrong.
Okay, so what can you do about your development environment that is apparently missing something for CORS to work properly:
Are you in control of the server? Can you add custom headers? If the answer is "yes", then make sure that your server responds with this header (you should not use the wildcard symbol
for production only within your development environment - see [3] and [4]) - just like the services from jsontest.com:
Access-Control-Allow-Origin: *
This is the easiest and the preferred approach and doesn't require any browser configuration.
If you are not in control of the server then the "Force CORS" Firefox Add-on [5] you've mentioned should do the trick. Just append ?alloworigin=false to the http://echo.jsontest.com URL I've used in the playground sample to prevent jsontest.com from sending the Access-Control-Allow-Origin header. After installing and manually enabling "Force CORS" I could see the expected response in the browser console too.
So my assumption is that while you disabled "the safe browsing and the strict origin policy" you maybe messed something up. Can you restore the original settings and try out just the server config adaption or the "Force CORS" Add-on? Did you enable the "Force CORS" Add-on manually in the Add-on bar?
See also:
