best way to do cross-site request?

I am still at getting the token. When I run the code below I get a whole slew of fields about myself in response.

 response=
"{
"id": "1109308060260095483xx",
"email": "[email protected]",
"verified_email": true,
"name": "Richard Berns",
"given_name": "Richard",
"family_name": "Berns",
"link": "https://plus.google.com/1109308060260095483xx",
"picture": "https://lh4.googleusercontent.com/-tzUZ4ZmxxJM/AAAAAAAAAAI/AAAAAAAAAAA/HDERazJjQtE/photo.jpg",
"gender": "male"
}
"



        var x = new XMLHttpRequest();
          x.addEventListener("load",reqListener);   //this callabck means we got the email
          x.open('GET', 'https://www.googleapis.com/oauth2/v2/userinfo?alt=json&access_token=' + token);
          x.send();
  

function reqListener(){
console.log(this.response["email"]);
}     

But I only need the response.email field. I will use this as the key that I send to my CI daemon. How do I access the email field in response? My plan is to build a new XMLHttpRequest() to go over to the CI daemen directly in reqListener(). Any pros or cons?

proof that an old dog can learn new tricks