Let’s start with the MDN docs for the base element, they say: The HTML <base> element specifies the base URL to use for all relative URLs contained within a document.

That sounds like it could be pretty useful. You could change the base to be the root, so there would be no more getting relative/absolute URLs mixed up.

<head>
    <base href="/">
</head>

<a href="test">Relative URL</a>
<a href="/test">Absolute URL</a>
<a href="https://google.co.uk">External URL</a>

If the code above was run on martinblackburn.co.uk/some-page, then each of the URL’s would go to the following places:

URL with base without base
test martinblackburn.co.uk/test martinblackburn.co.uk/some-page/test
/test martinblackburn.co.uk/test martinblackburn.co.uk/test
https://google.co.uk https://google.co.uk https://google.co.uk

Target

You can also specify a target on the base element.

<head>
    <base href="/" target="_blank">
</head>

This is a much nicer way to open all URLs in a new window, better than the javascript option I did previously.

You can overwrite each URL to open where you want, so <a href='/some-page' target='_self'>Some page</a> will make that link open in the same window.