Summarize three methods of implementing Ajax cross-domain in PHP

With the popularity of front-end and back-end separation, it has become a common operation in web development for the front-end to call the back-end interface and obtain data through Ajax technology.

However, due to the browser's same-origin policy, web pages from different sources (different protocols, domain names or ports) cannot access each other's own DOM and cookies, which makes cross-domain access a very common requirement. There are many ways to solve this problem.

This article will introduce three ways to implement Ajax cross-domain in PHP.

1. JSONP

JSONP (JSON with Padding) is a very popular solution when the front end initiates cross-domain requests. It is actually a way to "cheat" the browser, taking advantage of the fact that the