JSFiddle - React, Tailwind, and code Playground

HTML

<a href="javascript:unhide('displaybx');">CLICK</a>
<div id="displaybx" class="hidden">Content to be revealed</div>

CSS

.hidden {display: none;}
.unhidden {display: block;}

JavaScript

<script type="text/javascript">
 function unhide(divID) {
 var item = document.getElementById(divID);
 if (item) {
 item.className=(item.className=='hidden')?'unhidden':'hidden';
 }
 }
</script>