Build, test, and debug regular expressions
Matches telephone numbers in international or national format. Accepts either an international prefix (00 or + followed by a 2-5 digit country code) or a leading 0 for domestic dialing, followed by 9-10 digits where the first digit cannot be zero. The gm flags allow validating each phone number on every line of multiline input. Useful for form validation of European-style phone numbers.