Doesn't seem to work – getposts.php returns an empty response, the URL in "Data Scraped from Facebook Page …" heading changes, but the posts displayed are still from that demo dog page.
EDIT: Upon further inspection, it does work for some pages, but not for all of them (even if they are public). Maybe some limitation by FB's page type/category?
I caution against trying to monetize it; Facebook will waste your time with constant cat and mouse changes to the HTML and will bully you with their vast legal resources
https://web.archive.org/web/20191119175736/https://nofb.pw/
but I found that successfully scraping the wide variety of FB page styles to be a non-stop effort, so results were patchy at best.
I wish you luck with yours tho, hope you have more success at it than I did.