JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">Foo
    <div id="bar">Bar</div>
</div>
<div id="resultat"></div>

CSS

#foo{
    display: none;
}

JavaScript

$(function(){
    $('#resultat').html(
        $('#bar').is(':visible') ?
        '#bar est visible' :
        '#bar n\'est pas visible'
    );
});