How to protect HTML form from blank submission

Question

Basically I\'m using this tutorial: HTML FORM

Everything is working as it should but one flow I\'ve found is that everyone can see the URL for your

Answer 1

(1) there should be no danger from someone 'just entering' the URL in their browser - the back-end code is supposed to respond only to POST, not to GET (entering a URL in a browser makes it issue a GET request for the given URL).

(2) the quoted example code already includes client-side validation (including checks for empty fields), so if someone legitimately uses your entry form, they will not be able to send a blank form.

(3) all that remains is to protect the back-end code from accidental or malicious posting of empty forms (and any other use that is undesirable). The example PHP code doesn't have any checks, you should add some - like the isset(...) or empty() checks suggested in another answer here).