JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<button class="btn btn-danger" 
  data-complete-text="Готово!"
  data-loading-text="Загружаю..."
>Обновить</button>

JavaScript

$('.btn').click(function() {
  var btn = $(this);
      btn.button('loading');

  $.get('/echo/json', function() {
    btn.button('complete');

    alert(btn.get(0).disabled);
    alert(btn.attr('class'));
  });
});