JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://goibibo.ibcdn.com/hotelsnew/static/js/lib/jquery.2.1.3.min.1459594795.js"></script>
<div style="float:left;width:100%;border:1px solid #000;">
<div id="dynamic-content" style="float:left;background-color:#090;border:1px solid #900">
<div style="float;left;">
Mango
</div>
<div style="float;left;margin-left:5px;">
Banana
</div>
<div style="float;left;margin-left:5px">
Orange
</div>
</div>
<div id="other-content" style="float:left;background-color:#630;border:1px solid #009;">
</div>
</div>

JavaScript

var items=["mango","grapes","banana"];
var windowWidth = $(window).width();
console.log(windowWidth);
var dynamicContentWidth = $("#dynamic-content").width();
console.log(dynamicContentWidth);
var otherContentWidth = dynamicContentWidth >= windowWidth ? windowWidth : windowWidth-dynamicContentWidth-20;

console.log(otherContentWidth);

$("#other-content").width(otherContentWidth);
$("#other-content").height($("#dynamic-content").height());