Translations:Using regular expressions/111/vi
From LimeSurvey Manual
/^(?:00:[0-5][0-9](?::[0-5][0-9])? (?:am|AM)|(?:0[1-9] |1[01]):[0-5][0-9](?::[0-5][0-9])? (?:[ap]m|[AP]M)|12:[ 0-5][0-9](?::[0-5][0-9])? (?:pm|PM))$/
/^(?:00:[0-5][0-9](?::[0-5][0-9])? (?:am|AM)|(?:0[1-9] |1[01]):[0-5][0-9](?::[0-5][0-9])? (?:[ap]m|[AP]M)|12:[ 0-5][0-9](?::[0-5][0-9])? (?:pm|PM))$/