fill-in field bank number + check afterwards??

[rmc]

Hello,

I've created a document with a fill-in field wich contains a bank
account nummber wich my colleagues need to fill in.

Now I want to add a check on this input to be sure the bank account
number is correct.

I saw some examples/functions for PHP and .NET but is this also possible
in a 'simple' Word document and how does this formula/solution work then?

thanks in advance for all suggestions!

sincerly, rmc