JSFiddle - React, Tailwind, and code Playground

HTML

<p id="grenaa">Click me!</p>

JavaScript

window.onload = function() {
    alert("hello!");
    
    // answering the event;
    document.getElementById("grenaa").onclick = function() {
        alert("Hello there!");
    };
    
    // invoking the click
    document.getElementById("grenaa").onclick();
};