in reply to
How to prevent a Reload from resubmitting a form?
By, rather than rendering an entire page as a response to the POST request, redirecting the user to another page where they can — for example — see the result of their query.
This way, the page they end up opening will be served by a GET request, which can be freely reloaded any time.
It is worth mentioning that you have resubmitted this question several times because of this very issue — and PerlMonks serving entire pages as results of POST requests.