JSFiddle - React, Tailwind, and code Playground
HTML
<ul class="sf-menu">
<li class="first"><a href="http://www.site.co.uk/en-us/home.aspx">Home</a></li>
<li class=""><a href="http://www.site.co.uk/en-us/aboutus/abgroup.aspx">About Us</a></li>
<li class=""><a href="http://www.site.co.uk/en-us/casestudies.aspx">Case Studies</a></li>
</ul>
JavaScript
$('a[href*="/aboutus/"]').css('background-color', 'red');
var match = window.location.match(/aboutus/);
$(match).css('border','')