JSFiddle - React, Tailwind, and code Playground

HTML

<base href="www.google.com" />

<div id="valueBefore"></div>
<div id="valueAfter"></div>

JavaScript

$('#valueBefore').text( $('base').attr('href') );
$('base').attr('href','kjhsgdkjahgdjkahgdf');
$('#valueAfter').text( $('base').attr('href') );