JSFiddle - React, Tailwind, and code Playground

HTML

<a href="http://www.google.com">External link #1</a><br />
<a href="ftp://www.donotinclude.dk">No match link #1</a><br />
<a href="?nope">No match link #2</a><br />
<a href="https://www.google.dk">External link #2</a><br />
<a href="http://www.google.se">External link #3</a><br />
<a href="ssh://whywouldyouevendothis">No match link #3</a><br />
<a href="https://www.google.co.uk">External link #4</a><br />
<a href="http://www.facebook.com">External link #5</a><br />
<a href="/index.html">No match link #4</a><br />
<a href="https://www.facebook.com">External link #6</a><br />

JavaScript

$.expr[':'].exturl = function(obj) {
    return (/^https?:\/\//i).test($(obj).attr("href"));
}
$(document).ready(function() {
    $("a:exturl").css("color", "red");
});