JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">width of: </div>
<div id="content">the margin of: </div>

CSS

#content {
    margin-left: 100px;
}

#wrapper {
    width: 0px;
}

JavaScript

$().ready(function() {
      var w = $('#content').css("margin-left");
      $('#content').append($('#content').css("margin-left"));
      $('#wrapper').css("width", w);
      $('#wrapper').append(w);
    });