JSFiddle - React, Tailwind, and code Playground

HTML

<div id="desktop">
    <div class="window" id="win_1" title="Finder">
        <h1 class="titlebar">Title bar</h1>
        <div class="content">
            <p>Dette er en test</p>
        </div>
    </div>
</div>

CSS

#win_1 {
    height: 250px;
    width: 200px;
}

JavaScript

$(document).ready( function()
{
    $("#win_1 .content").html('width: ' + $("#win_1").width() + '<br />height: ' + $("#win_1").height());
});