Need help validating a form with dynamic fields

I'm dynamically generating form elements.  for example, each user has
many magazine subscriptions.  So I make a checkbox for each
subscription named something like "name_${subscriptionID}".  How can I
write a validator when the name isn't known?

I want to validate that every field that starts with the string
"name_" has a valid integer.

How can I do this?

-- 
Matthew Wilson
[email protected]
http://tplus1.com
216-470-6058

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