The perfect solution to cross-domain requests (JSONP, CORS) (picture and text tutorial, with code)

Now I will bring you a perfect solution for cross-domain requests (JSONP, CORS). Let me share it with you now and give it as a reference for everyone.

A well-known problem is that Ajax directly requests ordinary files, which causes cross-domain unauthorized access. Solutions include JSONP, Flash, etc.

JSONP

We found that when calling js files on a Web page, it is not affected by whether it is cross-domain or not. Anyone with the "src" attribute All tags have cross-domain capabilities, such as