How to get jsonp data?

Question

JavaScript

Hello!
The server supports jsonp request. I use this code:

var URL; // сама ссылка на json файл.
 var xhr = new XMLHttpRequest();

 xhr.responseType = 'json';

 xhr.addEventListener('load', function(evt) {
   if (xhr.status === 200) {
     console.log(xhr.response);
   } else {
     console.error(xhr.status);
   }
 });
  xhr.open('GET', URL);
  xhr.send();

Received a file in the Network tab in Chrome, the file says:
/**/ typeof callbackName === 'function' && callbackName([{"name":"Name",...}])
(... -- t .e. a lot of data)
How can I use (display) this data, how to transfer it, I can’t understand, I can’t get it xhr.response writes null in the console . If not for this line, I would have easily received arrays of objects. In addition, please give links where work with jsonp is described, please.