Strptime() implementation in javascript

If you need a simply strptime() implementation for Javascript feel free to use the following. I needed this for more sane date formatting in SpurTracer. If you find this useful or find bugs please post a comment!

// Copyright (c) 2012 Lars Lindner <[email protected]>
//
// GPLv2 and later or MIT License - http://www.opensource.org/licenses/mit-license.php

var dayName = new Array("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun");
var monthName = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dez");
   
/* simulates some of the format strings of strptime() */
function strptime(format, date) {
	var last = -2;
	var result = "";
	var hour = date.getHours();

	/* Expand aliases */
	format = format.replace(/%D/, "%m/%d/%y");
	format = format.replace(/%R/, "%H:%M");
	format = format.replace(/%T/, "%H:%M:%S");

	/* Note: we fail on strings without format characters */

	while(1) {
		/* find next format char */
		var pos = format.indexOf('%', last + 2);

		if(-1 == pos) {
			/* dump rest of text if no more format chars */
			result += format.substr(last + 2);
			break;
		} else {
			/* dump text after last format code */
			result += format.substr(last + 2, pos - (last + 2));

			/* apply format code */
			formatChar = format.charAt(pos + 1);
			switch(formatChar) {
				case '%':
					result += '%';
					break;
				case 'C':
					result += date.getYear();
					break;
				case 'H':
				case 'k':
					if(hour < 10) result += "0";
					result += hour;
					break;
				case 'M':
					if(date.getMinutes() < 10) result += "0";
					result += date.getMinutes();
					break;
				case 'S':
					if(date.getSeconds() < 10) result += "0";
					result += date.getSeconds();
					break;
				case 'm':
					if(date.getMonth() < 10) result += "0";
					result += date.getMonth();
					break;
				case 'a':
				case 'A':
					result += dayName[date.getDay() - 1];
					break;
				case 'b':
				case 'B':
				case 'h':
					result += monthName[date.getMonth()];
					break;
				case 'Y':
					result += date.getFullYear();
					break;
				case 'd':
				case 'e':
					if(date.getDate() < 10) result += "0";
					result += date.getDate();
					break;
				case 'w':
					result += date.getDay();
					break;
				case 'p':
				case 'P':
					if(hour < 12) {
						result += "am";
					} else {
						result += "pm";
					}
					break;
				case 'l':
				case 'I':
					if(hour % 12 < 10) result += "0";
					result += (hour % 12);
					break;
			}
		}
		last = pos;
	}
	return result;
}