yui3 xdr with credentials

xdr.js

YUI({ filter:'raw' }).use('node-event-delegate', 'io-xdr', function (Y) {
  var followList = Y.one('#onboard');

  followList.delegate('click', function(e) {
    e.preventDefault();
    var url = this.ancestor('form').getAttribute('action');
    console.log(url);

    var handleSuccess = function(id, o, a) {
        console.log('success');
    };

    var handleFailure = function(id, o, a) {
        console.log('failure');
    };

    var cfg = {
      method: 'GET',
      xdr: {
        use: "native",
        credentials: true
      },
      headers: {
        'Accept': 'application/json'
      },
      on: {
        success: handleSuccess,
        failure: handleFailure
      }
    };

    console.log(Y.io(url, cfg));

  }, 'button');
});


// make sure your server returns the following headers:
// Access-Control-Allow-Origin: http://yourhostname.com // this should match the 'Origin' header sent by the browser
// Access-Control-Allow-Credentials: true