JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="menu">
<li><a href="javascript:void(0);">list 01</a></li>
    <li><a href="http://fiddle.jshell.net/kachibito/ZVWUh/6/show/light/">list 02</a></li>
<li><a href="javascript:void(0);">list 03</a></li>
<li><a href="javascript:void(0);">list 04</a></li>
</ul>

CSS

ul{margin:25px;}
li{float:left;margin-left:10px;}
.current{color:red;border-bottom:1px solid #000;}

JavaScript

var url = window.location;
        $('.menu a[href="'+url+'"]').addClass('current');