JavaScript Date.format

UPDATE: This code has been moved to a GitHub repository. Please go there for the latest information and downloads. github.com/jacwright/date.format


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 \\i\\s \\h\\e\\r\\e!'));

Will output ““. Here are the format options that may be used (taken from php.net and modified a bit):

format character Description Example returned values
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 (added in PHP 5.1.0) 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 (added in PHP 4.1.0) 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. (added in PHP 5.1.0) 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 (added in PHP 5.1.0) Examples: UTC, GMT, Atlantic/Azores
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
c ISO 8601 date (added in PHP 5) 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()

MIT Licensed!

And here is the format function in all its glory: (Note: Updated 9/25/2010 with some additional characters implemented thanks to Tomas Theunissen, updated 9/29/2010 with addition from D’n Russler, updated 2/8/2013 with an addition from Haravikk)

// Simulates PHP's date function
Date.prototype.format = function(format) {
    var returnStr = '';
    var replace = Date.replaceChars;
    for (var i = 0; i < format.length; i++) {       var curChar = format.charAt(i);         if (i - 1 >= 0 && format.charAt(i - 1) == "\\") {
            returnStr += curChar;
        }
        else if (replace[curChar]) {
            returnStr += replace[curChar].call(this);
        } else if (curChar != "\\"){
            returnStr += curChar;
        }
    }
    return returnStr;
};

Date.replaceChars = {
    shortMonths: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
    longMonths: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
    shortDays: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],
    longDays: ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'],

    // Day
    d: function() { return (this.getDate() < 10 ? '0' : '') + this.getDate(); },
    D: function() { return Date.replaceChars.shortDays[this.getDay()]; },
    j: function() { return this.getDate(); },
    l: function() { return Date.replaceChars.longDays[this.getDay()]; },
    N: function() { return this.getDay() + 1; },
    S: function() { return (this.getDate() % 10 == 1 && this.getDate() != 11 ? 'st' : (this.getDate() % 10 == 2 && this.getDate() != 12 ? 'nd' : (this.getDate() % 10 == 3 && this.getDate() != 13 ? 'rd' : 'th'))); },
    w: function() { return this.getDay(); },
    z: function() { var d = new Date(this.getFullYear(),0,1); return Math.ceil((this - d) / 86400000); }, // Fixed now
    // Week
    W: function() { var d = new Date(this.getFullYear(), 0, 1); return Math.ceil((((this - d) / 86400000) + d.getDay() + 1) / 7); }, // Fixed now
    // Month
    F: function() { return Date.replaceChars.longMonths[this.getMonth()]; },
    m: function() { return (this.getMonth() < 9 ? '0' : '') + (this.getMonth() + 1); },
    M: function() { return Date.replaceChars.shortMonths[this.getMonth()]; },
    n: function() { return this.getMonth() + 1; },
    t: function() { var d = new Date(); return new Date(d.getFullYear(), d.getMonth(), 0).getDate() }, // Fixed now, gets #days of date
    // Year
    L: function() { var year = this.getFullYear(); return (year % 400 == 0 || (year % 100 != 0 && year % 4 == 0)); },   // Fixed now
    o: function() { var d  = new Date(this.valueOf());  d.setDate(d.getDate() - ((this.getDay() + 6) % 7) + 3); return d.getFullYear();}, //Fixed now
    Y: function() { return this.getFullYear(); },
    y: function() { return ('' + this.getFullYear()).substr(2); },
    // Time
    a: function() { return this.getHours() < 12 ? 'am' : 'pm'; },
    A: function() { return this.getHours() < 12 ? 'AM' : 'PM'; },
    B: function() { return Math.floor((((this.getUTCHours() + 1) % 24) + this.getUTCMinutes() / 60 + this.getUTCSeconds() / 3600) * 1000 / 24); }, // Fixed now
    g: function() { return this.getHours() % 12 || 12; },
    G: function() { return this.getHours(); },
    h: function() { return ((this.getHours() % 12 || 12) < 10 ? '0' : '') + (this.getHours() % 12 || 12); },
    H: function() { return (this.getHours() < 10 ? '0' : '') + this.getHours(); },
    i: function() { return (this.getMinutes() < 10 ? '0' : '') + this.getMinutes(); },
    s: function() { return (this.getSeconds() < 10 ? '0' : '') + this.getSeconds(); },
    u: function() { var m = this.getMilliseconds(); return (m < 10 ? '00' : (m < 100 ?
'0' : '')) + m; },
    // Timezone
    e: function() { return "Not Yet Supported"; },
    I: function() {
        var DST = null;
            for (var i = 0; i < 12; ++i) {
                    var d = new Date(this.getFullYear(), i, 1);
                    var offset = d.getTimezoneOffset();

                    if (DST === null) DST = offset;
                    else if (offset < DST) { DST = offset; break; }                     else if (offset > DST) break;
            }
            return (this.getTimezoneOffset() == DST) | 0;
        },
    O: function() { return (-this.getTimezoneOffset() < 0 ? '-' : '+') + (Math.abs(this.getTimezoneOffset() / 60) < 10 ? '0' : '') + (Math.abs(this.getTimezoneOffset() / 60)) + '00'; },
    P: function() { return (-this.getTimezoneOffset() < 0 ? '-' : '+') + (Math.abs(this.getTimezoneOffset() / 60) < 10 ? '0' : '') + (Math.abs(this.getTimezoneOffset() / 60)) + ':00'; }, // Fixed now
    T: function() { var m = this.getMonth(); this.setMonth(0); var result = this.toTimeString().replace(/^.+ \(?([^\)]+)\)?$/, '$1'); this.setMonth(m); return result;},
    Z: function() { return -this.getTimezoneOffset() * 60; },
    // Full Date/Time
    c: function() { return this.format("Y-m-d\\TH:i:sP"); }, // Fixed now
    r: function() { return this.toString(); },
    U: function() { return this.getTime() / 1000; }
};

Or the minified version:

// Simulates PHP's date function
Date.prototype.format=function(e){var t="";var n=Date.replaceChars;for(var r=0;r<e.length;r++){var i=e.charAt(r);if(r-1>=0&&e.charAt(r-1)=="\\"){t+=i}else if(n[i]){t+=n[i].call(this)}else if(i!="\\"){t+=i}}return t};Date.replaceChars={shortMonths:["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"],longMonths:["January","February","March","April","May","June","July","August","September","October","November","December"],shortDays:["Sun","Mon","Tue","Wed","Thu","Fri","Sat"],longDays:["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"],d:function(){return(this.getDate()<10?"0":"")+this.getDate()},D:function(){return Date.replaceChars.shortDays[this.getDay()]},j:function(){return this.getDate()},l:function(){return Date.replaceChars.longDays[this.getDay()]},N:function(){return this.getDay()+1},S:function(){return this.getDate()%10==1&&this.getDate()!=11?"st":this.getDate()%10==2&&this.getDate()!=12?"nd":this.getDate()%10==3&&this.getDate()!=13?"rd":"th"},w:function(){return this.getDay()},z:function(){var e=new Date(this.getFullYear(),0,1);return Math.ceil((this-e)/864e5)},W:function(){var e=new Date(this.getFullYear(),0,1);return Math.ceil(((this-e)/864e5+e.getDay()+1)/7)},F:function(){return Date.replaceChars.longMonths[this.getMonth()]},m:function(){return(this.getMonth()<9?"0":"")+(this.getMonth()+1)},M:function(){return Date.replaceChars.shortMonths[this.getMonth()]},n:function(){return this.getMonth()+1},t:function(){var e=new Date;return(new Date(e.getFullYear(),e.getMonth(),0)).getDate()},L:function(){var e=this.getFullYear();return e%400==0||e%100!=0&&e%4==0},o:function(){var e=new Date(this.valueOf());e.setDate(e.getDate()-(this.getDay()+6)%7+3);return e.getFullYear()},Y:function(){return this.getFullYear()},y:function(){return(""+this.getFullYear()).substr(2)},a:function(){return this.getHours()<12?"am":"pm"},A:function(){return this.getHours()<12?"AM":"PM"},B:function(){return Math.floor(((this.getUTCHours()+1)%24+this.getUTCMinutes()/60+this.getUTCSeconds()/3600)*1e3/24)},g:function(){return this.getHours()%12||12},G:function(){return this.getHours()},h:function(){return((this.getHours()%12||12)<10?"0":"")+(this.getHours()%12||12)},H:function(){return(this.getHours()<10?"0":"")+this.getHours()},i:function(){return(this.getMinutes()<10?"0":"")+this.getMinutes()},s:function(){return(this.getSeconds()<10?"0":"")+this.getSeconds()},u:function(){var e=this.getMilliseconds();return(e<10?"00":e<100?"0":"")+e},e:function(){return"Not Yet Supported"},I:function(){var e=null;for(var t=0;t<12;++t){var n=new Date(this.getFullYear(),t,1);var r=n.getTimezoneOffset();if(e===null)e=r;else if(r<e){e=r;break}else if(r>e)break}return this.getTimezoneOffset()==e|0},O:function(){return(-this.getTimezoneOffset()<0?"-":"+")+(Math.abs(this.getTimezoneOffset()/60)<10?"0":"")+Math.abs(this.getTimezoneOffset()/60)+"00"},P:function(){return(-this.getTimezoneOffset()<0?"-":"+")+(Math.abs(this.getTimezoneOffset()/60)<10?"0":"")+Math.abs(this.getTimezoneOffset()/60)+":00"},T:function(){var e=this.getMonth();this.setMonth(0);var t=this.toTimeString().replace(/^.+ \(?([^\)]+)\)?$/,"$1");this.setMonth(e);return t},Z:function(){return-this.getTimezoneOffset()*60},c:function(){return this.format("Y-m-d\\TH:i:sP")},r:function(){return this.toString()},U:function(){return this.getTime()/1e3}}