JSFiddle - React, Tailwind, and code Playground

HTML

<div class="submenu">Hello</div>
<div class="submenu">Hello</div>
<div class="submenu">Hello</div>
<div class="submenu">Hello</div>
<div class="submenu">Hello</div>
<div class="submenu">Hello</div>

JavaScript

var submenus = document.getElementsByClassName("submenu");
	for (var i = 0; i < submenus.length; i++) {
	    submenus[i].onclick = (function(j) {
	        return function () {
	            alert(j);
	        };
	    })(i);
	}