JSFiddle - React, Tailwind, and code Playground

HTML

<body id="-1">

<p id="3.14">click here to set variable to 3.14</p>
<h3 id="5">click here to set variable to 5</h3>
<p id ="2">click here to set variable to 2</p>
<p id ="2310">click here to set variable to 2310</p>


<div id="load"></div>

CSS

#load{
    background: #faa;
}

JavaScript

document.body.onmousedown = whichElement;
var output = document.getElementById("load")
function whichElement(e) {
    e = e || window.event;
    var targ = e.target || e.srcElement;
    if (targ.nodeType===3) {// defeat Safari bug
        targ = targ.parentNode;
    }
    output.innerHTML=targ.innerHTML;
}