javascript date format 日期格式化

index.js

/*
demo 
today = new Date();
var dateString = today.format("dd-m-yy");
alert(dateString);

source	http://jsfiddle.net/phZr7/1/

	 * Date Format 1.2.3
	 * (c) 2007-2009 Steven Levithan <stevenlevithan.com>
	 * MIT license
	 *
	 * Includes enhancements by Scott Trenda <scott.trenda.net>
	 * and Kris Kowal <cixar.com/~kris.kowal/>
	 *
	 * Accepts a date, a mask, or a date and a mask.
	 * Returns a formatted version of the given date.
	 * The date defaults to the current date/time.
	 * The mask defaults to dateFormat.masks.default.
	 */

	var dateFormat = function() {
		var token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g, timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g, timezoneClip = /[^-+\dA-Z]/g, pad = function(val, len) {
			val = String(val);
			len = len || 2;
			while (val.length < len)
			val = "0" + val;
			return val;
		};

		// Regexes and supporting functions are cached through closure
		return function(date, mask, utc) {
			var dF = dateFormat;

			// You can't provide utc if you skip other args (use the "UTC:" mask prefix)
			if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) {
				mask = date;
				date = undefined;
			}

			// Passing date through Date applies Date.parse, if necessary
			date = date ? new Date(date) : new Date;
			if (isNaN(date))
				throw SyntaxError("invalid date");

			mask = String(dF.masks[mask] || mask || dF.masks["default"]);

			// Allow setting the utc argument via the mask
			if (mask.slice(0, 4) == "UTC:") {
				mask = mask.slice(4);
				utc = true;
			}

			var _ = utc ? "getUTC" : "get", d = date[_ + "Date"](), D = date[_ + "Day"](), m = date[_ + "Month"](), y = date[_ + "FullYear"](), H = date[_ + "Hours"](), M = date[_ + "Minutes"](), s = date[_ + "Seconds"](), L = date[_ + "Milliseconds"](), o = utc ? 0 : date.getTimezoneOffset(), flags = {
				d : d,
				dd : pad(d),
				ddd : dF.i18n.dayNames[D],
				dddd : dF.i18n.dayNames[D + 7],
				m : m + 1,
				mm : pad(m + 1),
				mmm : dF.i18n.monthNames[m],
				mmmm : dF.i18n.monthNames[m + 12],
				yy : String(y).slice(2),
				yyyy : y,
				h : H % 12 || 12,
				hh : pad(H % 12 || 12),
				H : H,
				HH : pad(H),
				M : M,
				MM : pad(M),
				s : s,
				ss : pad(s),
				l : pad(L, 3),
				L : pad(L > 99 ? Math.round(L / 10) : L),
				t : H < 12 ? "a" : "p",
				tt : H < 12 ? "am" : "pm",
				T : H < 12 ? "A" : "P",
				TT : H < 12 ? "AM" : "PM",
				Z : utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""),
				o : (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
				S : ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]
			};

			return mask.replace(token, function($0) {
				return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);
			});
		};
	}();

	// Some common format strings
	dateFormat.masks = {
		"default" : "ddd mmm dd yyyy HH:MM:ss",
		shortDate : "m/d/yy",
		mediumDate : "mmm d, yyyy",
		longDate : "mmmm d, yyyy",
		fullDate : "dddd, mmmm d, yyyy",
		shortTime : "h:MM TT",
		mediumTime : "h:MM:ss TT",
		longTime : "h:MM:ss TT Z",
		isoDate : "yyyy-mm-dd",
		isoTime : "HH:MM:ss",
		isoDateTime : "yyyy-mm-dd'T'HH:MM:ss",
		isoUtcDateTime : "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"
	};

	// Internationalization strings
	dateFormat.i18n = {
		dayNames : ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
		monthNames : ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]
	};

	// For convenience...
	Date.prototype.format = function(mask, utc) {
		return dateFormat(this, mask, utc);
	};