JSFiddle - React, Tailwind, and code Playground

HTML

<div id="myDiv">
    This div has a scroll bar.
</div>

<br />

<div id="results">
</div>

CSS

#myDiv {
    width: 200px;
	overflow-y: scroll;
}

JavaScript

// Webkit browsers return viewports not including the scrollbar when looking in element.style.width
// jQuery corrects for this but forgets to when the case is not lowercase only.

var lowerOnly =  $("#myDiv").css("width");
var mixedCase =  $("#myDiv").css("wIdTh");

$("#results").html("width: " + lowerOnly + " <br /> " + "wIdTh: " + mixedCase);