HTML
<body>
<h1>Element Dimensions</h1>
<section class="output">
<h2 class="visually-hidden">Output</h2>
<p class="client-width">clientWidth: <span>0px</span></p>
<p class="offset-width">offsetWidth: <span>0px</span></p>
<p class="scroll-width">scrollWidth: <span>0px</span></p>
</section>
<section class="showcase">
<h2 class="visually-hidden">Showcase</h2>
<button class="overflow">hide overflow</button>
<div class="container">
<p class="peacock">pump me</p>
</div>
</section>
</body>