JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content" style="display: none">
    Page content.
</div>

<div id="loading" style="display: block">
    Loading! Please calm down guy...
</div>

JavaScript

// Just to simulates loading delay.
var i = setInterval(function () {
    clearInterval(i);

    // The desired code is only this:
    document.getElementById("loading").style.display = "none";
    document.getElementById("content").style.display = "block";
   
});