XMLHttpRequest (Ajax): CORS

The same source principle of the browser makes XMLHttpRequest unable to communicate across domains. There are many abnormal practices to achieve cross-origin. Among them, the jsonp solution is more elegant, but jsonp is limited to the get method, and other methods cannot be implemented.

W3C issued a standard in 2009. You only need to use access-control-allow-origin in the response header to implement cross-origin communication. For example:

HTTP/1.1 200 okaccess-control-allow-origin :*

Of course, if you want to be compatible with the old IE8, you still have to find the jsonp solution or implement the old abnormal IFRAME solution.

References:

Http://www.w3.org/TR/cors/

XMLHttpRequest (Ajax): CORS