JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/axios/dist/axios.min.js"></script>

<span id="status">Vazio</span>
<button id="ajax">Go!</button>
<hr>
<div id="feedback" class="hidden">Carregando</div>

CSS

.hidden {
  display: none;
}

JavaScript

var button = document.getElementById('ajax');
var feedback = document.getElementById('feedback');
var status = document.getElementById('status');

button.addEventListener('click', event => {
  feedback.classList.remove('hidden');
  
  axios.get('https://httpbin.org/delay/2')
    .then(response => {
      status.innerHTML = 'OK';
    })
    .catch(erros => {
      status.innerHTML = "Erro ao carregar dados.";
    })
    .then(() => {
      feedback.classList.add('hidden');
    })
});