A Simple javascript function to format date. Pass a date as an argument and get formatted date. I needed a JavaScript date format function such as the Visual Basic Format function, in which you can pass a format string and get the formatted string back; my first approach was to issue a series of consecutive and "destructive" replace calls, but upon discovering that the 5.5 (or higher) version of JScript supported the use of a function as the replaceTextargument of the replace method, I got creative. Here's an example call of what I wanted: SomeDiv.innerText = (new Date()).format('dddd, mmmm dd, yyyy.'); This would display: Saturday, July 16, 2005 So in my first approach, I globally and case-insensitively replaced dddd with the corresponding string, which "destroyed" every occurrence, so that later in the code I could replace dd with the date number. This worked just fine, but I knew that by inspecting the format specifier for a match, I could skip the search of every format specifier; say I only want the month and the date; well, by switching upon the format specifier (or rather "datepart" specifier), the year replacement will never be issued. Get it? The fun part relies in the use of a function in the replaceText argument of the replace method; this way the $1 property as a function argument always represents the last match. Other considerations include the format or "datepart" specifiers: none other than yyyy will be parsed as the year; months and days have the usual three flavors of fullname (mmmm), three-letter (mmm) or numeric (mm); hours (hh) can be rectified to the 12-hour format with the a/p specifier, and minutes (nn) and seconds (ss) may also be specified. Javascript Function // a global month names array var gsMonthNames = new Array( 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December' ); // a global day names array var gsDayNames = new Array( 'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday' ); // the date format prototype Date.prototype.format = function(f) { if (!this.valueOf()) return 'Â '; var d = this; return f.replace(/(yyyy|mmmm|mmm|mm|dddd|ddd|dd|hh|nn|ss|a\/p)/gi, function($1) { switch ($1.toLowerCase()) { 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 ((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'; } } ); } http://dlvr.it/4p6bnX
