JSFiddle - React, Tailwind, and code Playground

HTML

<div id="userLiivaneLord">
    LiivaneLord
</div>

<input type="submit" value="Suurenda teksti"
onclick="eval(document.getElementById('LiivaneLordCode').innerHTML)"/>

<div class="code" id="LiivaneLordCode">
    document.getElementById("userLiivaneLord").innerHTML = document.getElementById("userLiivaneLord").innerHTML+" "
    document.getElementById("userLiivaneLord").style.fontSize = document.getElementById("userLiivaneLord").innerHTML.length+"px";
</div>

<div class="code" id="OlaviCode">
    alert('boo!');
</div>

CSS

.code {
    visibility:hidden;
}