XML HTTP Request in JS

XMLHttpRequest.js

const request = new XMLHttpRequest();
request.open('GET', 'https://example.com/api/data', true);

request.onload = function() {
  if (this.status >= 200 && this.status < 400) {
    // Success!
    const data = JSON.parse(this.response);
    console.log(data);
  } else {
    // We reached our target server, but it returned an error
    console.error('Server returned an error');
  }
};

request.onerror = function() {
  // There was a connection error of some sort
  console.error('Connection error');
};

request.send();