User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:16.0) Gecko/20100101 Firefox/16.0 Build ID: 20121024073032 Steps to reproduce: I have a website at "example.com" and I am serving all external resources from "cdn.example.com". So in my HTML page at "example.com" I have something like: <script type="text/javascript" src="http://cdn.example.com/script.js"></script> In my script I want to create a web worker, so I do: worker = new Worker("http://cdn.example.com/script.js"); Actual results: This fails on Firefox 16 with "Failed to load script: http://cdn.example.com/script.js (nsresult = 0x805303f4)" error. It works on Safari 6 and Chrome 22. It seems the problem is because origins differ. Effective origin of the script is "example.com" and "cdn.example.com" does not match that. This seems a bug because not CORS not setting "document.domain" helps (or at least I couldn't make it to work by playing with that). I tried also setting CPS headers to "x-content-security-policy: default-src 'self' example.com cdn.example.com" but it still does not work. Expected results: That a script loaded by a page could execute itself as a web worker (which works in Safari 6 and Chrome 22). Or that at least some other way of enabling this would work.

This should be fixed for Firefox 18. Could you check to see if this is working as it should in nightlies or aurora?