To avoid complications when working with regular expressions, it's essential to ensure that backreferences are used only when their corresponding groups are successfully matched. www fairplay24.in

For javascript - var Regex_Pattern = /\d{8}|^(\d{2}-){3}\d{2}$/;

However, some flavors, like JavaScript, treat backreferences to non-participating groups as matching an empty string, allowing the overall match to succeed. Betbhai9 login

Regex_Pattern = r"\d{8}|^(\d\d)(-\d\d){2}-(\d\d)$"

^\d{2}(-?)\d{2}(\1\d{2}){2}$