<nav>
<ul>
<li><a href="/">Home</a></li>
<li><a href="/about/">About</a></li>
<li><a href="/clients/">Clients</a></li>
<li><a href="/contact/">Contact Us</a></li>
</ul>
</nav>
css
js
$(function() {
$('nav a[href^="/' + location.pathname.split("/")[1] + '"]').addClass('active');
});