Here is a list of all the date formats available for formatting.

Format  Description                                                               Example returned values
------  -----------------------------------------------------------------------   -----------------------
  d     Day of the month, 2 digits with leading zeros                             01 to 31
  D     A short textual representation of the day of the week                     Mon to Sun
  j     Day of the month without leading zeros                                    1 to 31
  l     A full textual representation of the day of the week                      Sunday to Saturday
  N     ISO-8601 numeric representation of the day of the week                    1 (for Monday) through 7 (for Sunday)
  S     English ordinal suffix for the day of the month, 2 characters             st, nd, rd or th. Works well with j
  w     Numeric representation of the day of the week                             0 (for Sunday) to 6 (for Saturday)
  z     The day of the year (starting from 0)                                     0 to 364 (365 in leap years)
  W     ISO-8601 week number of year, weeks starting on Monday                    01 to 53
  F     A full textual representation of a month, such as January or March        January to December
  m     Numeric representation of a month, with leading zeros                     01 to 12
  M     A short textual representation of a month                                 Jan to Dec
  n     Numeric representation of a month, without leading zeros                  1 to 12
  t     Number of days in the given month                                         28 to 31
  L     Whether it's a leap year                                                  1 if it is a leap year, 0 otherwise.
  o     ISO-8601 year number (identical to (Y), but if the ISO week number (W)    Examples: 1998 or 2004
        belongs to the previous or next year, that year is used instead)
  Y     A full numeric representation of a year, 4 digits                         Examples: 1999 or 2003
  y     A two digit representation of a year                                      Examples: 99 or 03
  a     Lowercase Ante meridiem and Post meridiem                                 am or pm
  A     Uppercase Ante meridiem and Post meridiem                                 AM or PM
  g     12-hour format of an hour without leading zeros                           1 to 12
  G     24-hour format of an hour without leading zeros                           0 to 23
  h     12-hour format of an hour with leading zeros                              01 to 12
  H     24-hour format of an hour with leading zeros                              00 to 23
  i     Minutes, with leading zeros                                               00 to 59
  s     Seconds, with leading zeros                                               00 to 59
  u     Decimal fraction of a second                                              Examples:
        (minimum 1 digit, arbitrary number of digits allowed)                     001 (i.e. 0.001s) or
                                                                                  100 (i.e. 0.100s) or
                                                                                  999 (i.e. 0.999s) or
                                                                                  999876543210 (i.e. 0.999876543210s)
  O     Difference to Greenwich time (GMT) in hours and minutes                   Example: +1030
  P     Difference to Greenwich time (GMT) with colon between hours and minutes   Example: -08:00
  T     Timezone abbreviation of the machine running the code                     Examples: EST, MDT, PDT ...
  Z     Timezone offset in seconds (negative if west of UTC, positive if east)    -43200 to 50400
  c     ISO 8601 date
        Notes:                                                                    Examples:
        1) If unspecified, the month / day defaults to the current month / day,   1991 or
           the time defaults to midnight, while the timezone defaults to the      1992-10 or
           browser's timezone. If a time is specified, it must include both hours 1993-09-20 or
           and minutes. The "T" delimiter, seconds, milliseconds and timezone     1994-08-19T16:20+01:00 or
           are optional.                                                          1995-07-18T17:21:28-02:00 or
        2) The decimal fraction of a second, if specified, must contain at        1996-06-17T18:22:29.98765+03:00 or
           least 1 digit (there is no limit to the maximum number                 1997-05-16T19:23:30,12345-0400 or
           of digits allowed), and may be delimited by either a '.' or a ','      1998-04-15T20:24:31.2468Z or
        Refer to the examples on the right for the various levels of              1999-03-14T20:24:32Z or
        date-time granularity which are supported, or see                         2000-02-13T21:25:33
        http://www.w3.org/TR/NOTE-datetime for more info.                         2001-01-12 22:26:34
  U     Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)                1193432466 or -2138434463
  MS    Microsoft AJAX serialized dates                                           \/Date(1238606590509)\/ (i.e. UTC milliseconds since epoch) or
                                                                                  \/Date(1238606590509+0800)\/