This was developed to allow for the formatting of dates in JavaScript and ActionScript like PHP can do. I actually just took the documentation from the PHP date function and went down the list implementing every option that I could do easily. I know more support could be added, but I didn’t need it (and still don’t). If anyone embellishes on this let me know and we can post better versions!

Using it is simple, but you may need to refer to the available format string options often to remember how to use it. I always need to refer to PHP’s date documentation every time I use it. You may also escape letters to make them literal, but be sure to escape your escape so Javascript can handle the string correctly.

var myDate = new Date();
alert(myDate.format('M jS, Y'));
alert(myDate.format('M jS, Y \\i\\s \\h\\e\\r\\e!'));

Will output "Dec 16th, 2013" and "Dec 16th, 2013 is here!". Here are the format options that may be used (taken from php.net and modified a bit):

c

Format character	Description	Example
Day
d	Day of the month, 2 digits with leading zeros	01 to 31
D	A textual representation of a day, three letters	Mon through Sun
j	Day of the month without leading zeros	1 to 31
l	A full textual representation of the day of the week	Sunday through 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) through 6 (for Saturday)
z	The day of the year (starting from 0)	0 through 365
Week
W	ISO-8601 week number of year, weeks starting on Monday	Example: 42 (the 42nd week in the year)
Month
F	A full textual representation of a month, such as January or March	January through December
m	Numeric representation of a month, with leading zeros	01 through 12
M	A short textual representation of a month, three letters	Jan through Dec
n	Numeric representation of a month, without leading zeros	1 through 12
t	Number of days in the given month	28 through 31
Year
L	Whether it’s a leap year	1 if it is a leap year, 0 otherwise.
o	ISO-8601 year number. This has the same value as Y, except that if the ISO week number (W) belongs to the previous or next year, that year is used instead.	Examples: 1999 or 2003
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
Time
a	Lowercase Ante meridiem and Post meridiem	am or pm
A	Uppercase Ante meridiem and Post meridiem	AM or PM
B	Swatch Internet time	000 through 999
g	12-hour format of an hour without leading zeros	1 through 12
G	24-hour format of an hour without leading zeros	0 through 23
h	12-hour format of an hour with leading zeros	01 through 12
H	24-hour format of an hour with leading zeros	00 through 23
i	Minutes with leading zeros	00 to 59
s	Seconds, with leading zeros	00 through 59
Timezone
e (unsuported)	Timezone identifier	UTC, GMT, Atlantic/Azorest
I	Whether or not the date is in daylights savings time	1 if Daylight Savings Time, 0 otherwise.
O	Difference to Greenwich time (GMT) in hours	Example: +0200
P	Difference to Greenwich time (GMT) with colon between hours and minutes (added in PHP 5.1.3)	Example: +02:00
T	Timezone setting of this machine	Examples: EST, MDT
Z	Timezone offset in seconds. The offset for timezones west of UTC is always negative, and for those east of UTC is always positive.	-43200 through 43200
Full Date/Time
ISO 8601 date	2004-02-12T15:19:21+00:00
r	RFC 2822 formatted date	Example: Thu, 21 Dec 2000 16:01:07 +0200
U	Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)	See also time()

Contributors:

• Jacob Wright
• Tomas Theunissen
• D’n Russler
• Haravikk