Checking inputfields
 

I've added an extra inputfield in newthread en editpost.
It all works like a charm.

However, I want to force the users to use this field.

I tried to make some code, it gives an error message, but it still contiues posting the thread!

Where in wich file should I place my checkup-code (so it gives the error message, but doesn't update/post the thread)?

/includes/functions_newpost.php

i would assume:)

Uhum, but where in that file should I place the code?

I mean, at wich point in the file it is proceeding to edit or post a thread?