JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>
<div class="big-square">
	<div class="small-button">button</div>
</div>

CSS

.big-square{
  background-color: #f44336;
  height: 200px;
  width: 200px;
}
.small-button{
  background-color: white;
  width: 70px;
  display: none;
}
.big-square:hover .small-button{
  display: block;
}

JavaScript

$('.small-button').on('click', function() {
  $('.small-button').html('clicked')
})