JSFiddle - React, Tailwind, and code Playground

HTML

<head>
    <script>
         var treasure="";
function magic(obj){
    treasure=obj;
}
function domagic(){
    treasure.style.backgroundColor="red";
}
    </script>
</head>
<div onclick="magic(this)" style="width:100px;height:100px;border:1px solid black"></div>
<div onclick="magic(this)" style="width:100px;height:100px;border:1px solid black"></div>
<input type="button" onclick="domagic()" value="Do Magic">