JSFiddle - React, Tailwind, and code Playground

HTML

<button id="button1">button1</button>
<button id="button2">button2</button>

JavaScript

document.getElementById('button1').addEventListener('click', function(){
    alert('Hello World');
});


var func = function(){
    alert('Hello World, it is me again.');
};

document.getElementById('button2').addEventListener('click', func);