JSFiddle - React, Tailwind, and code Playground

HTML

<h1>loading…</h1>

JavaScript

//same as $(document).on('load'…
$(document).load(function(){
    $("h1").append('loaded');
});

$(document).on('load',function(){
    $("h1").append('on(load)');
});

$(document).ready(function(){
    //immediately called
    $("h1").append('ready');
});

$(document).on('ready',function(){
    //never called, because we're already ready
    $("h1").append('on(ready)');
});