JSFiddle - React, Tailwind, and code Playground

HTML

<div id="example">Some Content</div>
<div id="the_margin" style="font-weight: bold;">The left margin is:</div>

CSS

#example {
    -webkit-margin: 0 auto 0;
    -moz-margin: 0 auto 0;
    width: 300px;
    border: 1px solid #CCC;
}

JavaScript

$(document).ready(function () {
    $("#the_margin").append($("#example").css("margin-left"));
});