>>>I have an application that has to run in 14 languages and 17 countries. I check for counrty, use this method for U.S. and allow 'free form' in non-U.S. because of all the weird(to me!) phone formats around the world.
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>>I like this idea for U.S. phone numbers too. Is there any reason to format US phone numbers, especially when some have extensions and some do not?
>
>Yes, there's an insurmountable one :) Users do not like it from a readability aspect. Extensions go into a separate field, as they vary in length.

Ah, yes, the user. I keep trying to forget about them :).