JSFiddle - React, Tailwind, and code Playground

HTML

<div id="msgBox">
    <div class="msgContent">
        1234
    </div>
</div>
<button onclick="insertIntoMsgBox('I'm red on yellow bg')">Insert into msgContent (it's not easy)</button>

CSS

#msgBox {background-color: yellow}
.msgContent {color: red}

JavaScript

// DO NOT TOUCH!!!
function insertIntoMsgBox() { // oooh, no.. msgContent.. good bye!
  var element = getElementById("msgBox");
    element.innerHTML = "MESSAGE";
}

// DO ALL WHAT YOU WANT
function