JSFiddle - React, Tailwind, and code Playground

HTML

<button id="icon">Test Button</button>
<div id="test" style="display: none;">I am hidden</div>

CSS

#test {
    color: #000;
}

JavaScript

document.getElementById('icon').onclick = function(){
    var el = document.getElementById('test');
    if ( el.style.display != 'none' ){
        el.style.display = 'none';
    }
    else {
        el.style.display = 'block';
    };
};