class: code
- / to validate patrons' phone numbers.
- Example ^((\+)?[1-9]{1,2})?([-\s\.])?((\(\d{1,4}\))|\d{1,4})(([-\s\.])?[0-9]{1,12}){1,2}$
- (Source of example http://regexlib.com/REDetails.aspx?regexp_id=3009)
- (Source of example <a href="http://regexlib.com/REDetails.aspx?regexp_id=3009">RegExLib.com</a>)
- Leave blank to accept any phone number.
-