JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#">Hello!</a>
<div class="overlay" style="display: none">asdasd</div>

CSS

.overlay { display: none; width:100%; height: 1000px; z-index:9; opacity: 0.7; background-color: #000; position:fixed; top:0; left:0; bottom:0; right:0; }

JavaScript

$('a').click(function(){
    alert("clicked");
    $('.overlay').show();
})