It's a proposal. I made this thing: https://github.com/ryancdotorg/VerifyJS https://github.com/ryancdotorg/VerifyJS but it requires CORS headers from the CDN

It's a proposal. I made this thing: https://github.com/ryancdotorg/VerifyJS https://github.com/ryancdotorg/VerifyJS but it requires CORS headers from the CDN and isn't well tested.