JSFiddle - React, Tailwind, and code Playground

HTML

<div id='black'></div>
<a href='#' id='clck'>Click</a>
<br /><Br />
<img src='http://www.google.ru/images/nav_logo40.png'>

CSS

#black{    
  position: absolute;
  top: 0px; left: 0px; right: 0px; bottom: 0px;
  background: #000;
  opacity: 0.5;
  display: none;
}
#clck{
    position: absolute;
    z-index:2;
    background: white;
    padding: 6px;
}

JavaScript

$("#clck").click(function(){
    $("#black").toggle();
})