var gsMonthNames = new Array(
'January',
'February',
'March',
'April',
'May',
'June',
'July',
'August',
'September',
'October',
'November',
'December'
);
var gsDayNames = new Array(
'Sunday',
'Monday',
'Tuesday',
'Wednesday',
'Thursday',
'Friday',
'Saturday'
);

Date.prototype.format = function(f)
{
    if (!this.valueOf())
        return ' ';

    var d = this;

    return f.replace(/(yyyy|mmmm|mmm|mm|dddd|ddd|dd|hh|nn|ss|a\/p|sup|HH)/gi,
        function($1)
        {
            switch ($1)
            {
            case 'yyyy': return d.getFullYear();
            case 'mmmm': return gsMonthNames[d.getMonth()];
            case 'mmm':  return gsMonthNames[d.getMonth()].substr(0, 3);
            case 'mm':   return (d.getMonth() + 1).zf(2);
            case 'dddd': return gsDayNames[d.getDay()];
            case 'ddd':  return gsDayNames[d.getDay()].substr(0, 3);
            case 'dd':   return d.getDate().zf(2);
            case 'HH':   return d.getHours().zf(2);
            case 'hh':   return ((h = d.getHours() % 12) ? h : 12).zf(2);
            case 'nn':   return d.getMinutes().zf(2);
            case 'ss':   return d.getSeconds().zf(2);
            case 'a/p':  return d.getHours() < 12 ? 'a' : 'p';
	        case 'sup':  switch (d.getDate())
                        {
                        case 1:
                        case 21:
                        case 31:
                        return "st";
                        case 2:
                        case 22:
                        return "nd";
                        case 3:
                        case 23:
                        return "rd";
                        default:
                        return "th";
                        }
            }
        }
    );
}
// Zero-Fill
String.prototype.zf = function(l) { return '0'.string(l - this.length) + this; }

// VB-like string
String.prototype.string = function(l) { var s = '', i = 0; while (i++ < l) { s += this; } return s; }

Number.prototype.zf = function(l) { return this.toString().zf(l); }