handle unnamed JSONP in xmlHttpRequest Javascript [duplicate]

I have simple XMLHttpRequest.

  var xhr = new XMLHttpRequest();
  xhr.open("GET", url, true);

  xhr.onreadystatechange = function () {
    if (this.readyState == 4 && this.status == 200) {
      console.log(this.responseText);
    }
  };

  xhr.send();

As you can see that I’m printing this.responseText in the console which outputs something like following

({ "status": "success", "data": { "title": "Post1" })

How can I get the JSON inside. I am totally aware of JSONP concepts but I don’t want $.ajax in jQuery, I’m trying to achieve this via javascript. Thanks