- var_dump: documentation ( source)
- mktime: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
var_dump(mktime(12, 00, 00));
var_dump(strtotime('12:00 pm'));
var_dump(strtotime('01:23'));
date('H:i:s', strtotime('12:00 pm') + strtotime('01:23'));