Is this the best way to save objects into variable?

Question

This is my ajax request:

var headingArr = [];
var firstParaArr = [];
var secParaArr = [];
var i = 0;

(function getAjx() {

   var xhr = new XMLHttpRequest();
   var url = 'https://api.myjson.com/bins/13vg19';

   xhr.open('GET', url, true);
   xhr.setRequestHeader('Content-Type', 'application/json');
   xhr.onreadystatechange = function()  {

      if (this.readyState === 4) {

         var res = JSON.parse(xhr.responseText);
         var resLen = res.length;

            for (;i<resLen;i++) {
               headingArr.push(res[i].heading);
               firstParaArr.push(res[i].body_one);
               secParaArr.push(res[i].body_two);
            }
      }
      else {
            console.log(this.status);
         }
   }
   xhr.send();
})();

console.log(headingArr + " " + firstParaArr + " " + secParaArr); // now we have them outside of the if scope.

Is this the best way to put the response (var res) outside of the self-invoking AJAX function?

Is there some neater way?

Thanks.