if(!Date.prototype.format) {
	
	    //Formats a JavaScript Date object to a string.
		//Following PHP's date() format -- 
		//http://php.net/manual/en/function.date.php
		Date.prototype.format = (function () {
		
			var pattern = {
				
					//Day of the month, 2 digits with leading zeros
					d: function () {
						var day = this.getDate();
						return day < 10 ? '0' + day : day;
					},
					
					//A textual representation of a day, three letters
					D: function () {
						return pattern['l'].call(this).slice(0,3);
					},
					
					//Day of the month without leading zeros
					j: function () {
						return this.getDate();
					},
					
					//A full textual representation of the day of the week
					l: function () {
						switch(this.getDay()) {
						case 0:
							return 'Sunday';
						case 1:
							return 'Monday';
						case 2:
							return 'Tuesday';
						case 3:
							return 'Wednesday';
						case 4:
							return 'Thursday';
						case 5:
							return 'Friday';
						case 6:
							return 'Saturday';
						}
					},
					
					//ISO-8601 numeric representation of the day of the week
					N: function () {
						return this.getDay() === 0 ? 7 : this.getDay();
					},
					
					//English ordinal suffix for the day of the month, 2 characters
					S: function () {
					
						if(this.getDate() > 3 && this.getDate() < 21) {
							return 'th';
						}
					
						switch(this.getDate().toString().slice(-1)) {
						case '1':
							return 'st';
						case '2':
							return 'nd';
						case '3':
							return 'rd';
						default:
							return 'th';
						}
					},
					
					//Numeric representation of the day of the week
					w: function () {
						return this.getDay();
					},
					
					//The day of the year (starting from 0)
					z: function () {
						return Math.floor(((this - new Date(this.getFullYear(), 0, 1)) / 86400000), 0);
					},
					
					//ISO-8601 week number of year, weeks starting on Monday
					W: function () {
						var start = new Date(this.getFullYear(), 0, 1);
						return Math.ceil((((this - start) / 86400000) + start.getDay() + 1) / 7);
					},
					
					//A full textual representation of a month, such as January or March
					F: function () {
						switch(this.getMonth()) {
						case 0:
							return 'January';
						case 1:
							return 'February';
						case 2:
							return 'March';
						case 3:
							return 'April';
						case 4:
							return 'May';
						case 5:
							return 'June';
						case 6:
							return 'July';
						case 7:
							return 'August';
						case 8:
							return 'September';
						case 9:
							return 'October';
						case 10:
							return 'November';
						case 11:
							return 'December';
						}
					},
					
					//Numeric representation of a month, with leading zeros
					m: function () {
						var month = this.getMonth()+1;
						return month < 10 ? '0' + month : month;
					},
					
					//A short textual representation of a month, three letters
					M: function () {
						return pattern['F'].call(this).slice(0,3);
					},
					
					//Numeric representation of a month, without leading zeros
					n: function () {
						return this.getMonth()+1;
					},
					
					//Number of days in the given month
					t: function () {
						return 32 - new Date(this.getFullYear(), this.getMonth(), 32).getDate();
					},
					
					//Whether it's a leap year
					L: function () {
						return new Date(this.getFullYear(), 1, 29).getDate() === 29 ? 1 : 0;
					},
					
					//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.
					O: function () {
						return null;
					},
					
					//A full numeric representation of a year, 4 digits
					Y: function () {
						return this.getFullYear();
					},
					
					//A two digit representation of a year
					y: function () {
						return this.getFullYear().toString().slice(-2);
					},
					
					//Lowercase Ante meridiem and Post meridiem
					a: function () {
						return this.getHours() < 12 ? 'am' : 'pm';
					},
					
					//Uppercase Ante meridiem and Post meridiem
					A: function () {
						return this.getHours() < 12 ? 'AM' : 'PM';
					},
					
					//Swatch Internet time
					B: function () {
						return null;
					},
					
					//12-hour format of an hour without leading zeros
					g: function () {
						var hours = this.getHours();
						return hours > 12 ? hours - 12 : hours;
					},
					
					//24-hour format of an hour without leading zeros
					G: function () {
						return this.getHours();
					},
					
					//12-hour format of an hour with leading zeros
					h: function () {
						var hours = pattern['g'].call(this);
						return hours < 10 ? '0' + hours : hours;
					},
					
					//24-hour format of an hour with leading zeros
					H: function () {
						var hours = pattern['G'].call(this);
						return hours < 10 ? '0' + hours : hours;
					},
					
					//Minutes with leading zeros
					i: function () {
						return this.getMinutes() < 10 ? '0' + this.getMinutes() : this.getMinutes();
					},
					
					//Seconds, with leading zeros
					s: function () {
						return this.getSeconds() < 10 ? '0' + this.getSeconds() : this.getSeconds();;
					},
					
					//Microseconds
					u: function () {
						return this.getMilliseconds();
					},
					
					//Timezone identifier
					e: function () {
						return null;
					},
					
					//Whether or not the date is in daylight saving time
					I: function () {
						return null;
					},
					
					//Difference to Greenwich time (GMT) in hours
					O: function () {
						var offset = this.getTimezoneOffset() / 60;
						return (offset < 0 ? '' : '+') + (offset < 10 ? '0' + offset : offset) + '00';
					},
					
					//Difference to Greenwich time (GMT) with colon between hours and minutes
					P: function () {
						var offset = pattern['O'].call(this);
						return offset.slice(0,3) + ':' + offset.slice(-2);
					},
					
					//Timezone abbreviation
					T: function () {
						return null;
					},
					
					//Timezone offset in seconds. The offset for timezones west of UTC is always negative, and for those east of UTC is always positive
					Z: function () {
						return parseInt(pattern['O'].call(this)) * 60;
					},
					
					//ISO 8601 date
					c: function () {
						function pad(x) {
							return x < 10 ? '0'+ x : x;
						}
						
						return this.getUTCFullYear() + '-'
								+ pad(this.getUTCMonth() + 1) + '-'
								+ pad(this.getUTCDate()) + 'T'
								+ pad(this.getUTCHours()) + ':'
								+ pad(this.getUTCMinutes()) + ':'
								+ pad(this.getUTCSeconds()) + 'Z';
					},
					
					//RFC 2822 formatted date
					r: function () {
						return this.toUTCString();
					},
					
					//Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)
					U: function () {
						return this.getTime();
					}
				};

			return function(formatString) {
				var builder = '',
					character = '';
				
				for (var i = 0; i <= formatString.length; i++) {
					character = formatString.charAt(i);
				
					if(pattern.hasOwnProperty(character)) {
						builder += pattern[character].call(this).toString();
					}
					else {
						builder += character;
					}
				}

				return builder;
			}
		}());
	
	}