Cross-Origin Resource Sharing

This document defines a mechanism to enable client-side cross-site requests. Specifications that want to enable cross-site requests in an API they define can use the algorithms defined by this specification. If such an API is used on http://example.org resources, a resource on http://hello-world.example can opt in using the mechanism described by this specification (e.g., specifying Access-Control-Allow-Origin: http://example.org as response header), which would allow that resource to be fetched cross-site from http://example.org.