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

A slight modification to Manish M Demblani's contribution above handles 4am (I got rid of the seconds section as I don't need it in my application)

^(([0-1]{0,1}[0-9]( )?(AM|am|aM|Am|PM|pm|pM|Pm))|(([0]?[1-9]|1[0-2])(:|\.)[0-5][0-9]( )?(AM|am|aM|Am|PM|pm|pM|Pm))|(([0]?[0-9]|1[0-9]|2[0-3])(:|\.)[0-5][0-9]))$

handles: 4am 4 am 4:00 4:00am 4:00 pm 4.30 am etc..