Test, validate and match regular expressions
Matches US phone numbers in a 10-digit format (area code, exchange code, and subscriber number) with flexible separators. It supports an optional leading country code '1', optional spaces and hyphens, and area codes written either plain (555) or in parentheses like (555). Accepts formats such as 555-555-5555, (555) 555-5555, 1-555-555-5555, and 5555555555. Ideal for validating US telephone input in web forms.