js date format

http://stackoverflow.com/questions/3552461/how-to-format-javascript-date

/*
 * Date Format 1.2.3
 * (c) 2007-2009 Steven Levithan <stevenlevithan.com>
 * MIT license
 *
 * Includes enhancements by Scott Trenda <scott.trenda.net>
 * and Kris Kowal <cixar.com/~kris.kowal/>
 *
 * Accepts a date, a mask, or a date and a mask.
 * Returns a formatted version of the given date.
 * The date defaults to the current date/time.
 * The mask defaults to dateFormat.masks.default.
 */

var dateFormat = function () {
    var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|‘[^‘]*‘/g,
        timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
        timezoneClip = /[^-+\dA-Z]/g,
        pad = function (val, len) {
            val = String(val);
            len = len || 2;
            while (val.length < len) val = "0" + val;
            return val;
        };

    // Regexes and supporting functions are cached through closure
    return function (date, mask, utc) {
        var dF = dateFormat;

        // You can‘t provide utc if you skip other args (use the "UTC:" mask prefix)
        if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) {
            mask = date;
            date = undefined;
        }

        // Passing date through Date applies Date.parse, if necessary
        date = date ? new Date(date) : new Date;
        if (isNaN(date)) throw SyntaxError("invalid date");

        mask = String(dF.masks[mask] || mask || dF.masks["default"]);

        // Allow setting the utc argument via the mask
        if (mask.slice(0, 4) == "UTC:") {
            mask = mask.slice(4);
            utc = true;
        }

        var _ = utc ? "getUTC" : "get",
            d = date[_ + "Date"](),
            D = date[_ + "Day"](),
            m = date[_ + "Month"](),
            y = date[_ + "FullYear"](),
            H = date[_ + "Hours"](),
            M = date[_ + "Minutes"](),
            s = date[_ + "Seconds"](),
            L = date[_ + "Milliseconds"](),
            o = utc ? 0 : date.getTimezoneOffset(),
            flags = {
                d:    d,
                dd:   pad(d),
                ddd:  dF.i18n.dayNames[D],
                dddd: dF.i18n.dayNames[D + 7],
                m:    m + 1,
                mm:   pad(m + 1),
                mmm:  dF.i18n.monthNames[m],
                mmmm: dF.i18n.monthNames[m + 12],
                yy:   String(y).slice(2),
                yyyy: y,
                h:    H % 12 || 12,
                hh:   pad(H % 12 || 12),
                H:    H,
                HH:   pad(H),
                M:    M,
                MM:   pad(M),
                s:    s,
                ss:   pad(s),
                l:    pad(L, 3),
                L:    pad(L > 99 ?Math.round(L /10): L),
                t:    H <12?"a":"p",
                tt:   H <12?"am":"pm",
                T:    H <12?"A":"P",
                TT:   H <12?"AM":"PM",
                Z:    utc ?"UTC":(String(date).match(timezone)||[""]).pop().replace(timezoneClip,""),
                o:(o >0?"-":"+")+ pad(Math.floor(Math.abs(o)/60)*100+Math.abs(o)%60,4),
                S:["th","st","nd","rd"][d %10>3?0:(d %100- d %10!=10)* d %10]};return mask.replace(token,function($0){return $0 in flags ? flags[$0]: $0.slice(1, $0.length -1);});};}();// Some common format strings
dateFormat.masks ={"default":"ddd mmm dd yyyy HH:MM:ss",
    shortDate:"m/d/yy",
    mediumDate:"mmm d, yyyy",
    longDate:"mmmm d, yyyy",
    fullDate:"dddd, mmmm d, yyyy",
    shortTime:"h:MM TT",
    mediumTime:"h:MM:ss TT",
    longTime:"h:MM:ss TT Z",
    isoDate:"yyyy-mm-dd",
    isoTime:"HH:MM:ss",
    isoDateTime:"yyyy-mm-dd‘T‘HH:MM:ss",
    isoUtcDateTime:"UTC:yyyy-mm-dd‘T‘HH:MM:ss‘Z‘"};// Internationalization strings
dateFormat.i18n ={
    dayNames:["Sun","Mon","Tue","Wed","Thu","Fri","Sat","Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"],
    monthNames:["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec","January","February","March","April","May","June","July","August","September","October","November","December"]};// For convenience...Date.prototype.format =function(mask, utc){return dateFormat(this, mask, utc);};