How to Send a Cross-Domain Post Request Via JavaScript

Cross domain POST request is not sending cookie Ajax Jquery

You cannot set or read cookies on CORS requests through JavaScript. Although CORS allows cross-origin requests, the cookies are still subject to the browser's same-origin policy, which means only pages from the same origin can read/write the cookie. withCredentials only means that any cookies set by the remote host are sent to that remote host. You will have to set the cookie from the remote server by using the Set-Cookie header.

How to send a cross domain ajax request

put it on top of config.php

 header('Access-Control-Allow-Origin: *');

Cross Domain XML POST

To enable cross-domain requests, you'll need to not only add the 'Access-Control-Allow-Origin' to XXX, but you'll also need to make sure that the domain that you're submitting your request from, is allowed.

More information can be found here.

Workaround for Cross Domain Request

CORS (Cross-Origin Resource Sharing) is a system, consisting of transmitting HTTP headers, that determines whether browsers block frontend JavaScript code from accessing responses for cross-origin requests. (https://developer.mozilla.org/en-US/docs/Glossary/CORS)

You cannot inject JavaScript into a window when cross-origin resource sharing is disabled and this is by design.

Possible workarounds:

Change CORS headers on the server of Urltwo
~~Fetch source of Urltwo via an HTTP request and render it in a blank iframe (applicability will vary)~~. Edit: If the request is initiated from JavaScript, this will be subject to CORS as well.

If you have access to the server serving Urltwo, changing CORS settings is the best solution.
If you do not have access to the server, but you can edit the document served at Urltwo, you can communicate between the documents via document.postMessage (https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage) or by encoding information in the URL (query string or hash).
If you have access to neither, you can use a proxy that fetches the contents at Urltwo, sents the correct CORS headers and sends the result back to you.

What triggers cross-domain violation when AJAX request?

Due to this:

A resource is cross-origin when it's located at a different
(sub)domain, protocol, or port!

You should also use exact match host so http://www.example.com/bar doesn't work out.

Take a look at this to see more examples.

You should not get CORS in the A option.

And also this article fully describing CORS.