JSFiddle - React, Tailwind, and code Playground

by Jerrygoyal

HTML

<div class='mydiv'>

</div>

CSS

.mydiv{
  width:100px;
  height:100px;
  resize:both;
    overflow:auto;
  border:solid 2px blue;
}

JavaScript

var observer = new MutationObserver(function(mutations) {
    alert('size changed!');
  });
  var target = document.querySelector('.mydiv');
  observer.observe(target, {
    attributes: true
  });