Check value from database (in formbuilder?)

[Decorsign]

Good morning,

Does anyone know a solution for me.
I am trying to create a postal code and housenumber checker.

By adding postal codes to a database, i need a check form, witch can verify that the user is in the right postal code area.

It looks simple to me:

Add all postal codes (and house numbers) to a database or textfile.
Check if the postal code is in the database.
If so... Go to submission form
Otherwise... Show message...

Does Formbuilder solve this issue?

Thanx for any ideas.

[Peciura]

I would do such error check with jQuery and AJAX.