JSFiddle - React, Tailwind, and code Playground

HTML

<p id="demo">demo</p>
<p id="status">it will get changed when demo changed</p>
<button onclick="document.getElementById('demo').innerHTML='changed'">click</button>

JavaScript

var MutationObserver = window.MutationObserver || window.WebKitMutationObserver || window.MozMutationObserver;
  var target = document.querySelector('#demo');
 
  var observer = new MutationObserver(function(mutations) {
    mutations.forEach(function(mutation) {
      if (mutation.type === 'childList') {
      console.log(mutation.type);
       document.getElementById('status').innerHTML='changed';
      }
    });
  });
 
  observer.observe(target, {
  	attributes: true,
  	childList: true,
  	characterData: true
   });