Hi!

I would like LS to validate entry of a certain n-digit number (card id number9. For my case it must be a 15-digit number. But respondent must also have an option to enter just number 9 (if he doesn't know his card id number).

So only valid answers are digit 9 or any 15-digit number.

LS version on which survey is running is 1.91+.

I'm am aware of RegEx for 15-digit number /[0-9]{15}/ but I don't know how to let user to be able to enter digit 9 as well.

Thank you,

Andrej

Hi,

Not sure (i'm not a regexp expert ...)

But, maybe:
Denis
PS: oups, Tony read question better than me, my english is very poor ....

I think that will allow a 15-digit number or a 9-digit number.

How about:

.

Indeed, that works perfectly!