HTTP request headers via AJAX in JavaScript

Using the headers setting, you can send HTTP request headers:

public/client.jsbutton.addEventListener('click', function() {
  let promise = fetch('/handler/', {
    headers: {
      name1: 'value1',
      name2: 'value2',
    }
  });
});

Задание 1

Pass the Content-Type header to a server with the text/plain value.

Задание 2

Study the list of forbidden request headers.