Regex Tester & Validator

Validates Vietnamese full names line by line: each word must start with an ASCII uppercase letter (A–V only) followed by one or more lowercase letters, including Vietnamese diacritic vowels like à, ế, ộ, ữ, ư, and đ. Multiple name parts (given, middle, family) are allowed when separated by single spaces, e.g. 'Nguyễn Văn An'. Useful for form input validation, though it rejects initials like Đ, Ư, or W–Z.