preg match expression to check the 24 hour time format 01:00 to 24:59 code example
Example: 12 hrs for preg match with single and double digit in php
((1[0-2]|0?[1-9]):([0-5][0-9]) ?([AaPp][Mm]))
12:00 pm --------- OK
13:00
1:00 am --------- OK
5:5 am
5:05 PM --------- OK
55:55
09:59 // valid time, but meridiem is missing
:01
0:59
00:59 PM