JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">dfk</div>

JavaScript

window.onload = function() {
    
    function $(selector)
{
  var prefix = selector[0];
  selector = selector.substring(1);
  switch(prefix){
    case '#': return document.getElementById(selector);
    case '.': return document.getElementsByClassName(selector);
    default: return document.getElementsByTagName(prefix + selector);
  }
}

    
 var x = $('.wrapper');

for( i = 0; i < x.length; i++ ) {
 x[i].onclick = function() {
   alert('Hello world!');
 }
}
   
    
}