Javascript Date Utils

TSDateUtils.js

Date.prototype.format = function(pattern, utc)
	{
	if (!pattern) return pattern;

	var MonthsShort = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
	var MonthsLong  = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];
	
	var yyyy  = this[utc?'getUTCFullYear':'getFullYear']();
	var MM    = this[utc?'getUTCMonth'   :'getMonth']() + 1;
	var dd    = this[utc?'getUTCDate'    :'getDate']();
	var HH    = this[utc?'getUTCHours'   :'getHours']();
	var mm    = this[utc?'getUTCMinutes' :'getMinutes']();
	var ss    = this[utc?'getUTCSeconds' :'getSeconds']();
	var yy    = yyyy.toString().slice(-2);
	var apm   = HH >= 12? 'PM': 'AM';
	var hh    = HH >  12? HH - 12: HH;
	var tz    = utc? 0: this.getTimezoneOffset();
	var tzSgn = tz < 0? '-': '+';
	var tzHr  = ('0'+parseInt(Math.abs(tz/60))).slice(-2);
	var tzMin = ('0'+parseInt(Math.abs(tz%60))).slice(-2);
	
	var ret = pattern;
	ret = ret.replace('yyyy', yyyy);
	ret = ret.replace('yy', yy);
	ret = ret.replace('MMMM', MonthsLong[MM-1]);
	ret = ret.replace('MMM', MonthsShort[MM-1]);
	ret = ret.replace('MM', ('0'+MM).slice(-2));
	ret = ret.replace('M', MM);
	ret = ret.replace('dd', ('0'+dd).slice(-2));
	ret = ret.replace('d', dd);
	ret = ret.replace('HH', ('0'+HH).slice(-2));
	ret = ret.replace('H', HH);
	ret = ret.replace('hh', ('0'+hh).slice(-2));
	ret = ret.replace('h', hh);
	ret = ret.replace('mm', ('0'+mm).slice(-2));
	ret = ret.replace('m', mm);
	ret = ret.replace('ss', ('0'+ss).slice(-2));
	ret = ret.replace('s', ss);
	ret = ret.replace('aaaa', apm).replace('aaa', apm).replace('aa', apm).replace('a', apm);
	ret = ret.replace('z', 'GMT' + tzSgn + tzHr + ':' + tzMin);
	ret = ret.replace('Z', tzSgn + tzHr + tzMin);
	ret = ret.replace('XXX', tzSgn + tzHr + ':' + tzMin);
	ret = ret.replace('XX', tzSgn + tzHr + tzMin);
	ret = ret.replace('X', tzSgn + tzHr);
	
	return ret;
	}