XMLHttpRequest cannot load http://foo/bar. No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘http://localhost:8100’ is therefore not allowed access.
How to fix it, easy, developing with Chrome, just install the extension “Allow-Control-Allow-Origin: *” and you will be able to disable the CORS protection in any Chrome tab. Done. Working. Enjoy.
UPDATE: You can also run Chrome with a parameter to disallow all the security checks. For OSX, open Terminal and run: “open -a Google\ Chrome –args –disable-web-security”