How to substitute a protocol for all links on a page?

Question

PHP

Hello, please help.
There is a page, all links on it are OUTGOING, that is, to other sites.
If you write LINK , then the browser interpreter considers it a subfolder of the site. Is it
possible, with a small script, to add the protocol automatically to all hrefs, at least two slashes at the beginning?
I've looked all over the internet and it looks like this hasn't happened before. I really look forward to your help.

Answer 1

Under jQuery:

$('a').each(function () {
        let $this = $(this);
        $this.attr('href', 'http://' + $this.attr('href'));
});