Ajax请求子域

MDN has excellent details on this at https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy

The info there seems to indicate that this would be considered cross-domain. The real-world answer may depend on the browser. Best suggestion is "try it yourself" with a simple page in several browsers to see what happens.