Error in JSON APIs and Ajax: Access the JSON Data from an API

Tell us what’s happening:
In the instructions for this challenge, the instructions say:
On the right, click the “Get Message” button to load the freeCodeCamp Cat Photo API JSON into the HTML.
However, nothing happens when this button is clicked, so we can’t see the JSON data that the rest of the challenge refers to.

Your code so far

    req=new XMLHttpRequest();"GET",'/json/cats.json',true);
      // Add your code below this line

      // Add your code above this line
body {
  text-align: center;
  font-family: "Helvetica", sans-serif;
h1 {
  font-size: 2em;
  font-weight: bold;
.box {
  border-radius: 5px;
  background-color: #eee;
  padding: 20px 5px;
button {
  color: white;
  background-color: #4791d0;
  border-radius: 5px;
  border: 1px solid #4791d0;
  padding: 5px 10px 8px 10px;
button:hover {
  background-color: #0F5897;
  border: 1px solid #0F5897;
<h1>Cat Photo Finder</h1>
<p class="message">
The message will go here
<button id="getMessage">
  Get Message

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36.

Challenge: Access the JSON Data from an API

Link to the challenge:

A reply I just received to a post about another challenge in this section reveals the answer to this problem.
req=new HMLHttpRequest();
both need to be preceded by a variable keyword. Adding const to the start of these lines fixes the code.