JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://getfirebug.com/firebug-lite-debug.js"></script>
<div class="box"></div>
<div class="content"></div>

CSS

div {
    height: 120px;
    width: 100px;
    padding-top: 20px;
    padding-left: 10px;
    background-color: #abc;
    border: 1px solid black;
}
.box {
    box-sizing: border-box;
    -moz-box-sizing: border-box;
}

JavaScript

console.log("jQuery v" + $.fn.jquery);
showDimensions('box');
showDimensions('content');

function showDimensions(cls) {
    var elm = $('.' + cls),
        label = "$('." + cls + "')";

    console.log(label + ".height() = " + elm.height());
    console.log(label + ".css('height') = " + elm.css('height'));

    console.log(label + ".width() = " + elm.width());
    console.log(label + ".css('width') = " + elm.css('width'));
}