datetime format

RFC3339

2008-09-08T22:47:31-07:00

RFC2445 (iCalendar)

20121211155343

ISO8601

2008-12-19T16:39:57.67Z

ATOM = "Y-m-d\TH:i:sP";

COOKIE = "l, d-M-y H:i:s T";

ISO8601 = "Y-m-d\TH:i:sO";

RFC822 = "D, d M y H:i:s O";

RFC850 = "l, d-M-y H:i:s T";

RFC1036 = "D, d M y H:i:s O";

RFC1123 = "D, d M Y H:i:s O";

RFC2822 = "D, d M Y H:i:s O";

RFC3339 = "Y-m-d\TH:i:sP";

RSS = "D, d M Y H:i:s O";

W3C = "Y-m-d\TH:i:sP";




References :
PHP: DateTime - Manual