Date.prototype.format = function(str) { /* %A: Weekday (Monday - Sunday) %a: Weekday (Mon - Sun) %B: Month (January - December) %b: Month (Jan - Dec) %C: Year/100 (19 - 20) %c: Time and date (01/01/1900 12:00:00 AM - 12/31/2099 11:59:59 PM) [US format] %D: date (01/01/1900 - 12/31/2099) %d: Day (01 - 31) %e: Day ( 1 - 31) %F: Date (1900-01-01 - 2099-12-31) %G: ISO Year (1900 - 2099) [see http://en.wikipedia.org/wiki/ISO_8601#Week_dates] %g: ISO Year (00-99) [see http://en.wikipedia.org/wiki/ISO_8601#Week_dates] %H: Hour (00 - 23) %h: Month (Jan - Dec) [same as %b] %I: Hour (01 - 12) %j: Day of the year (001 - 366) %k: Hour ( 0-23) %l: Hour ( 1-12) %M: Minute (00 - 59) %m: Month (01 - 12) %n: Newline %p: AM/PM (AM - PM) %Q: Quarter (1 - 4) %R: Time (00:00 - 23:59) %r: Time (12:00:00 AM - 11:59:59 PM) %S: Second (00 - 59) %s: Number of seconds since the Epoch, UTC %T: Time (00:00:00 - 23:59:59) %t: Tab %U: Week (00 - 53) [Sunday as the first day of the week] %u: Weekday (1 - 7) [Monday as the first day of the week] %V: ISO Week (01 - 53) [see http://en.wikipedia.org/wiki/ISO_8601#Week_dates] %v: Date (1-Jan-1900 - 31-Dec-2099) %W: Week (00 - 53) [Monday as the first day of the week] %w: Weekday (1 - 7) [Sunday as the first day of the week] %X: Time (12:00:00 AM - 11:59:59 PM) [US format, same as %r] %x: Date (01/01/1900 - 12/31/2099) [US format, same as %D] %Y: Year (1900 - 2099) %y: Year (00 - 99) %Z: Time zone %z: Time zone offset (-1200 - +1200) %+: Date and Time (Mon Jan 1 00:00:00 GMT 1900 - Thu Dec 31 23:59:59 GMT 2099) %%: % */ var month = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']; var day = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']; var ampm = ['AM', 'PM']; str = str.replace(/%%/g, '<%>'); str = str.replace(/%c/g, '%x %X'); str = str.replace(/%X/g, '%r'); str = str.replace(/%x/g, '%D'); str = str.replace(/%D/g, '%m/%d/%y'); str = str.replace(/%F/g, '%Y-%m-%d'); str = str.replace(/%h/g, '%b'); str = str.replace(/%R/g, '%H:%M'); str = str.replace(/%r/g, '%I:%M:%S %p'); str = str.replace(/%T/g, '%H:%M:%S'); str = str.replace(/%w/g, '%e-%b-%Y'); str = str.replace(/%\+/g, '%a %b %e %H:%M:%S %Z %Y') str = str.replace(/%A/g, day[(this.getDay() + 6) % 7]); str = str.replace(/%a/g, day[(this.getDay() + 6) % 7].toString().substr(0, 3)); str = str.replace(/%B/g, month[this.getMonth()]); str = str.replace(/%b/g, month[this.getMonth()].toString().substr(0, 3)); str = str.replace(/%C/g, this.getFullYear().toString().substr(0, 2)); str = str.replace(/%d/g, this.getDate().toString().pad('0', 2, 'left')); str = str.replace(/%e/g, this.getDate().toString().pad(' ', 2, 'left')); str = str.replace(/%G/g, this.getISOYear()); str = str.replace(/%g/g, this.getISOYear().toString().substr(-2)); str = str.replace(/%H/g, this.getHours().toString().pad('0', 2, 'left')); str = str.replace(/%I/g, ((this.getHours() + 11) % 12 + 1).toString().pad('0', 2, 'left')); str = str.replace(/%j/g, this.getDayOfTheYear().toString().pad('0', 3, 'left')); str = str.replace(/%k/g, this.getHours().toString().pad(' ', 2, 'left')); str = str.replace(/%l/g, ((this.getHours() + 11) % 12 + 1).toString().pad(' ', 2, 'left')); str = str.replace(/%M/g, this.getMinutes().toString().pad('0', 2, 'left')); str = str.replace(/%m/g, (this.getMonth() + 1).toString().pad('0', 2, 'left')); str = str.replace(/%n/g, '\n'); str = str.replace(/%Q/g, Math.floor(this.getMonth() / 4) + 1); str = str.replace(/%p/g, ampm[Math.floor(this.getHours() / 12)]); str = str.replace(/%S/g, this.getSeconds().toString().pad('0', 2, 'left')); str = str.replace(/%s/g, this.getTime() / 1000); str = str.replace(/%t/g, '\t'); str = str.replace(/%U/g, Math.floor((this.getDayOfTheYear() + this.getFirstDayOfTheYear() - 1) / 7)); str = str.replace(/%u/g, (this.getDay() + 6) % 7); str = str.replace(/%V/g, this.getISOWeek()); str = str.replace(/%W/g, Math.floor((this.getDayOfTheYear() + (this.getFirstDayOfTheYear() + 6) % 7 - 1) / 7)); str = str.replace(/%w/g, this.getDay()); str = str.replace(/%Y/g, this.getFullYear()); str = str.replace(/%y/g, this.getFullYear().toString().substr(-2)); str = str.replace(/%Z/g, this.toString().substr(-4, 3)); str = str.replace(/%z/g, this.getTimezoneOffsetString()); str = str.replace(/<%>/g, '%'); return str; } Date.prototype.getFirstDayOfTheYear = function() { /* Weekday of January 1 of the current year (0 - 6) [Sunday as the first day of the week] */ var date = new Date(); date.setFullYear(this.getFullYear()) date.setMonth(0); date.setDate(1); return date.getDay(); } Date.prototype.getDayOfTheYear = function() { /* Day of the year (1 - 366) */ var days = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; var year = this.getFullYear(); var month = this.getMonth(); var day = this.getDate(); var dayOfTheYear = 0 for (var i = 0; i < month; i++) dayOfTheYear += days[month]; dayOfTheYear += day; if (month >= 2 && year % 4 == 0 && year % 400 != 0) dayOfTheYear++; return dayOfTheYear; } Date.prototype.getISOWeek = function() { /* ISO Week (1 - 53) [see http://en.wikipedia.org/wiki/ISO_8601#Week_dates] */ var date = new Date(); date.setTime(this.getTime() + (3 - (this.getDay() + 6) % 7) * 86400000); return Math.floor((date.getDayOfTheYear() + (date.getFirstDayOfTheYear() + 6) % 7 - 1) / 7) + 1; } Date.prototype.getISOYear = function() { /* ISO Year (1900 - 2099) [see http://en.wikipedia.org/wiki/ISO_8601#Week_dates] */ var date = new Date(); date.setTime(this.getTime() + (3 - (this.getDay() + 6) % 7) * 86400000); return date.getFullYear(); } Date.prototype.getTimezoneOffsetString = function() { /* Time zone offset string (-1200 - +1200) */ var offset = this.getTimezoneOffset(); if (offset < 0) var sign = '+'; else var sign = '-'; var hour = Math.floor(Math.abs(offset) / 60).toString().pad('0', 2, 'left'); var minute = (Math.abs(offset) % 60).toString().pad('0', 2, 'left'); return sign + hour + minute; }