Regex Tester & Validator

Validates UK/European day-first date-time strings (DD/MM/YYYY) with flexible separators (dash, space, slash, or dot). It checks day validity per month, handles leap years for February 29th (including century rules), and accepts years 1600-2999 or two-digit years. A trailing 24-hour time in HH:MM or HH:MM:SS format (optional seconds) is required. Useful for validating European-style datetime form inputs in JavaScript.