Regular expression for matching HH:MM time format

Question

I want a regexp for matching time in HH:MM format. Here\'s what I have, and it works:

^[0-2][0-3]:[0-5][0-9]$

This matches everything from

Answer 1

The best would be for HH:MM without taking any risk.

^(0[0-9]|1[0-9]|2[0-3]):[0-5][0-9]$