$re = '/([01][0-9]|2[0-3]):[0-5][0-9]
/mi';
$str = '20:59
00:59
01:01
10:30
00:00
24:59
30:01
00:60
05:122
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php