Use this little website to test if a URL is setup correctly to work with CORS.
For security, browsers stop scripts from accessing URLs on different domains. This is done via CORS or Cross-Origin Resource Sharing. It is implemented by looking at the HTTP headers returned by a url.
So if you are on
google.com and try to access
example.com/font.ttf, it will only be allowed if example.com returns a header allowing it. Learn more.
This site will make a test request to the URL and check if it has valid CORS headers. If it does, you should be good to go when using it in a browser. This website is open source and available here.
If you're loading a script or font, you'll want
GET. If you're sending an AJAX request to a URL, you probably want
OPTIONS for checking the preflight request. The other options are there just incase you need them.