JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div{
    width: 20rem;
    height: 15rem;
    background: yellow;
}

JavaScript

var div = document.getElementsByTagName("div")[0];
window.addEventListener("click", function(e){
    if (e.target != div)
        alert("Has dado un clic fuera del Div");
}, false);