JSFiddle - React, Tailwind, and code Playground

HTML

<div id='applicationArea'>
        <div id="orangeButton">Orange button</div>
    
    </div>

CSS

#orangeButton{
        background-color:orange;
        width:100px;
        height:100px;
        cursor:  crosshair;
    }
    #newDivThingy{
        background-color:green;
        width:100px;
        height:100px;
    }

JavaScript

var applicationArea = document.getElementById("applicationArea");
    var orangeButton = document.getElementById("orangeButton");
    
    
    orangeButton.onclick = function() {
      var newDivThingy = document.createElement("div");
      newDivThingy.id  = 'newDivThingy';  // I want each newly created div to have a numeric value concatenated to it's ID. IE newDivThingy1 newDivThingy2 newDivThingy3
      applicationArea.appendChild(newDivThingy);
    
    
    };