Access-Control-Allow-Methods: OPTIONS & CORS

Access-Control-Allow-Methods: OPTIONS

CORS

https://stackoverflow.com/questions/20478312/default-value-for-access-control-allow-methods

https://www.html5rocks.com/en/tutorials/cors/

https://www.w3.org/TR/cors/#preflight-request

https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS

https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Access-Control-Allow-Methods

Comma-delimited list of the allowed HTTP request methods.

Access-Control-Allow-Methods: POST, GET, OPTIONS

https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods

https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/OPTIONS

https://fetch.spec.whatwg.org/#http-access-control-allow-methods

https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#Preflighted_requests

demo

var invocation = new XMLHttpRequest();
var url = 'http://bar.other/resources/post-here/';
var body = '<?xml version="1.0"?><person><name>Arun</name></person>';

function callOtherDomain(){
  if(invocation)
    {
      invocation.open('POST', url, true);
      invocation.setRequestHeader('X-PINGOTHER', 'pingpong');
      invocation.setRequestHeader('Content-Type', 'application/xml');
      invocation.onreadystatechange = handler;
      invocation.send(body);
    }
}

// ......