Christian Wahl

I was about to answer a question on Stackoverflow, but then the question got deleted. So here I my answer.

The question was: How can I get a list of external links on a webpage?

My suggestion is to use the build-in list of links on document and then filter that on the origin of the current URL:

A simple HTML page:

<ul>
  <li><a href="/about">About</a></li>
  <li><a href="https://www.google.com">Google</a></li>
</ul>

The JavaScript:

var url = new URL(document.baseURI);
var origin = url.origin;
var external = [...document.links].filter(a => !a.href.startsWith(origin));

console.log(external);

Here I create a URL object based on the current baseURI of the document. Then I get the origin so that I can compare that with all the links. There can be different ways of writing URLs in the href attribute, but the href property will always return the absolute path that starts off with the origin. So, by testing if a href starts with the origin you can see if it is an internal or external link.