JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js" type="text/javascript"></script> 
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.9/jquery-ui.min.js" type="text/javascript"></script>
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.9/themes/base/jquery-ui.css" type="text/css" media="all" />


<div id="container">
    <div id="child"></div>
</div>

CSS

#container { width:100px; height:100px; border:1px solid red; }
#child{background:blue }

JavaScript

$("#container").resizable();
var parentwidth = $("#container").innerWidth();
var parentheight = $("#container").innerHeight();
$("#child").css({'width':parentwidth, 'height':parentheight});