JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="wrapper">
        <div class="vsbl"></div>
        <div class="hdn"></div>
    </div>    
    
</body>

CSS

.wrapper{
    height:300px;
    width:300px;
    border:1px solid black
}
.vsbl,.hdn{
    height:100px;
    width:70%;
    margin:10px;
    border:1px solid black;    
}
.hdn{
display:none;
}

JavaScript

$().ready(function(){
var content = "";
    content += $(".vsbl").width() + "<br>";
    content += $(".hdn").width();
    
    document.body.innerHTML += content;
    

    
});