Jump link to top of page

I have a list of items on a page set with jump links.
When I first coded the page, I used a relative url for the return link, using #pagetop. But WordPress turn that into this:
https://www.domain.com/page.php#pagetop, which then takes the user to the home page.

I have left the full url but removed page.php so now the return link is this:
https://www.domain.com/#pagetop
and it seems to be working.

Just posting in case it would help someone.