JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">

    <title>Test orgs</title>

    <script src="main.js"></script>
  </head>

  <body>
    
    <header>
    </header>

    <section>
    </section>

  </body>
</html>

JavaScript

var header = document.querySelector('header');
var section = document.querySelector('section');

var requestURL = 'http://127.0.0.1:3000/organizations.json';
      var request = new XMLHttpRequest();
      request.open('GET', requestURL);
      request.responseType = 'json';
      request.send();
      request.onload = function () {
        var organizations = request.response;
        populateHeader(organizations);
      }

      function populateHeader(jsonObj) {
        var myH1 = document.createElement('h1');
        myH1.textContent = jsonObj['organization'];
        header.appendChild(myH1);

        var myParagraph = document.createElement('p');
        myParagraph.textContent = 'Address is: ' + jsonObj['address'] + ', ' + jsonObj['addDetails'];
        header.appendChild(myParagraph);
      }