How to send a JSON object to a foreign API using the GET method from JS?

Question

JavaScript

You need to get data from the transport company. Their documentation says

To get the cost and delivery time, you need to send a json object to the CDEK server. When passing a json object, the appropriate Content-Type must be specified in the header.

api.cdek.ru/calculator/calculate_price_by_json.php
Content-Type: application/json
api.cdek.ru/calculator/calculate_price_by_jsonp.php
dataType : "jsonp" (from js)
api.cdek.ru/calculator/calculate_price_by_json_req...
Content-Type: application/x-www-form-urlencoded

How can this be done from JS? I asked tech support but they didn't help.

Answer 1

XMLHttp​Request​.set​Request​Header()
Using Fetch: Supplying Request Parameters

Answer 2

var xhr = new XMLHttpRequest();
xhr.open('GET', '/server', true);
xhr.onload = function () {
  // Запрос завершен. Здесь можно обрабатывать результат.
};
xhr.setRequestHeader('Content-Type', 'application/json');
xhr.send({ form: 'data' });

Well, something like this