JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<body>
<div id="bg">
</div>
<div id="box">
</div>
</body>
</html>

CSS

html, body {
    width:100%;
    height:100%;
}
#bg {
    width:100%;
    height:100%;
}
#box {
    position:absolute;
    top: 20px;
    left: 100px;
    width:100px;
    height:100px;
    background-color:blue;
}

JavaScript

var bg = document.getElementById("bg");
bg.addEventListener("click", clickBg, false);
var box = document.getElementById("box");
box.addEventListener("click", clickBox, false); 

function clickBg() {
   alert("Click on Background");
}

function clickBox() {
    alert("Click on Box");
}