JSFiddle - React, Tailwind, and code Playground

HTML

<button id="button1">Button 1</button>
<button id="button2">Button 2</button>

JavaScript

var clickFunction = function() {
    alert(this.id);
}
    
var obj1 = document.getElementById('button1');
var obj2 = document.getElementById('button2');

obj1.onclick = clickFunction;
obj2.onclick = clickFunction;