Response for preflight is invalid (redirect) error occur

Question

 test4 = () => {

        var xhr = new XMLHttpRequest();
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4 && xhr.status == 200) {
                var xmlDoc1 = xhr.responseText;
                console.log("?", xmlDoc1)
}
        xhr.open("GET",'http://www.naver.com');
 xhr.open("Access-Control-Allow-Origin",'http://www.naver.com');
        xhr.send();
        }
    }

componentDidMount() {
this.test4()
}

error ==> XMLHttpRequest cannot load http://www.naver.com/. Response for preflight is invalid (redirect) please help me...

Answer 1

There are a few problems here. Primarily though, CORS is preventing you from doing an XHR to www.naver.com. Unless you have some way to tell www.naver.com to allow you to make these types of requests, then you can't from a browser client.

First, the .open method is not used to add headers to a request. Second, Access-Control-Allow-Origin is a response header not a request header. It would make very little sense for the client to be able to declare the permitted access control to the server. Ref: MDN