How to send form data by POST request from “IE 11”?

Question

JavaScript

What is the correct way to send form data by POST request from "IE 11"?
Sending with AJAX, serializing with FormData() function -

let formData = new FormData(document.querySelector('#id_Form'));

.
Emptiness on the server comes from the "donkey". Other browsers send data normally.
Tried to add different headers -

xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

and 'form/multipart'- does not help. :(

Or any better "IE" ideas for working with FormData()?