Collecting a phone number as multiple fields rather than one [duplicate]

1. How do you format a phone number?
2. How are UK phone numbers formatted?

How do you format a phone number?

To format phone numbers in the US, Canada, and other NANP (North American Numbering Plan) countries, enclose the area code in parentheses followed by a nonbreaking space, and then hyphenate the three-digit exchange code with the four-digit number.

How are UK phone numbers formatted?

It has a four-digit area code (after the initial zero) and a six digit subscriber number, and is known as 4+6 format. These area codes were changed by adding a "1" directly after the initial zero as a part of PhONEday in 1995. Just short of 581 areas use this format, and the area codes range from 01200 to 01998.