A strftime implementation for JavaScript Date objects.

strftime.js

// https://gist.github.com/765200
var strftime;
strftime = (function () {

    var zeropad = function (n) {
        return n > 9 ? n : '0' + n;
    };

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

    var callbacks = {
        // Short day name (Sun-Sat)
        a: function (t) {
            return shortDays[t.getDay()];
        },
        // Long day name (Sunday-Saturday)
        A: function (t) {
            return days[t.getDay()];
        },
        // Short month name (Jan-Dec)
        b: function (t) {
            return shortMonths[t.getMonth()];
        },
        // Long month name (January-December)
        B: function (t) {
            return months[t.getMonth()];
        },
        // String representation (Thu Dec 23 2010 11:48:54 GMT-0800 (PST))
        c: function (t) {
            return t.toString();
        },
        // Two-digit day of the month (01-31)
        d: function (t) {
            return zeropad(t.getDate());
        },
        // Day of the month (1-31)
        D: function (t) {
            return t.getDate();
        },
        // Two digit hour in 24-hour format (00-23)
        H: function (t) {
            return zeropad(t.getHours());
        },
        // Hour in 24-hour format (0-23)
        i: function (t) {
            return t.getHours();
        },
        // Two digit hour in 12-hour format (01-12)
        I: function (t) {
            return zeropad(callbacks.l(t));
        },
        // Hour in 12-hour format (1-12)
        l: function (t) {
            var hour = t.getHours() % 12;
            return hour === 0 ? 12 : hour;
        },
        // Two digit month (01-12)
        m: function (t) {
            return zeropad(t.getMonth() + 1);
        },
        // Two digit minutes (00-59)
        M: function (t) {
            return zeropad(t.getMinutes());
        },
        // am or pm
        p: function (t) {
            return callbacks.H(t) < 12 ? 'am' : 'pm';
        },
        // AM or PM
        P: function (t) {
            return callbacks.H(t) < 12 ? 'AM' : 'PM';
        },
        // Two digit seconds (00-61)
        S: function (t) {
            return zeropad(t.getSeconds());
        },
        // Zero-based day of the week (0-6)
        w: function (t) {
            return t.getDay();
        },
        // Locale-specific date representation
        x: function (t) {
            return t.toLocaleDateString();
        },
        // Locale-specific time representation
        X: function (t) {
            return t.toLocaleTimeString();
        },
        // Year without century (00-99)
        y: function (t) {
            return zeropad(callbacks.Y(t) % 100);
        },
        // Year with century
        Y: function (t) {
            return t.getFullYear();
        },
        // Timezone offset (+0000)
        Z: function (t) {
            if (t.getTimezoneOffset() > 0) {
                return "-" + zeropad(t.getTimezoneOffset() / 60) + "00";
            } else {
                return "+" + zeropad(Math.abs(t.getTimezoneOffset()) / 60) + "00";
            }
        },
        // A percent sign
        '%': function(t) {
            return '%';
        }
    };

    /**
     * Returns a string of this date in the given +format+.
     */
    return function (date, format) {
        var regexp;
        date = date || new Date();
        for (var key in callbacks) {
            regexp = new RegExp('%' + key, 'g');
            format = format.replace(regexp, callbacks[key](date));
        }

        return format;
    };

})();
// TEST

function convertTime(u) {
    var date = new Date(u * 1000);
    return strftime(date, "%b %d, %Y %H:%M:%S");
}
var targetTime = "Jun 03, 2011 14:53:07";// 目標の形
// 入力値 = 1307080387682 は Fri Jun 03 2011 14:53:07 GMT+0900のUnixTime
console.log(1, targetTime === convertTime(1307080387));