Javascript localization part 1
Since the first edition of ECMAScript (ECMA-402) Javascript supports the output of language sensitive representation of a Date or Number object which is often overseen by many developers.

Take some seconds and thing about how you represent a date or number. Do you convert the object to a string and slices it at the needed position? Or do you extend the Date class and adds some new output representation functionality.

Since the ECMA-402 Standard, published on December 2012, you have some really great new functions which respects the locale settings of your environment.

Okey, lets take a step back. When I was working on my semantic web library calendar web component I searched for a way to represent a Date object inside the DOM tree in different way. One question was is how to represent a Date object in the format mmmm yyyy or mm/dd/yyyy. So I began to search for examples in the web and many entries dated back to 2009, 2010 and 2011. Some of them were also from 2013, which we really astound. Nonetheless, all answers had once thing in common. They put each component of the representation manually inside a string.

	var dateobj= new Date()
	dateobj.getDate() + "/" + dateobj.getMonth()+1 + "/" + dateobj.getFullYear()
	// 21/7/2014

or

	Date.locale = {
		en: {
			month_names: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
			month_names_short: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
		}
	};

	Date.prototype.getMonthName = function(lang) {
		lang = lang && (lang in Date.locale) ? lang : 'en';
		return Date.locale[lang].month_names[this.getMonth()];
	};
	Date.prototype.getMonthNameShort = function(lang) {
		lang = lang && (lang in Date.locale) ? lang : 'en';
		return Date.locale[lang].month_names_short[this.getMonth()];
	};

	// that can be used as follow:
	var now = new Date();
	now.getMonthNameShort + " " + now.getFullYear();
	// July 2014

The problem you have with these solutions is that they not respect the language sensitive representation of a Date or Number object.

The solution for this is quite simple. Javascript now provides different functions which respect the locale settings of the environment.

For the Date object now have these functions, whereas I personally prefer the toLocaleString()

Function Purpose
Date.prototype.toLocaleDateString() returns a string with a language sensitive representation of the date portion of this date.
Date.prototype.toLocaleString() returns a string with a language sensitive representation of this date.
Date.prototype.toLocaleTimeString() returns a string with a language sensitive representation of the time portion of this date.

You can use it as follow

	var now = new Date()
	date.toLocaleString('en', { month: 'long', year: 'numeric' });
	// July 2014
	date.toLocaleString('en', { month: '2-digit', day: '2-digit', year: 'numberic' });
	// 21/07/2014

where the first parameter is the locale and the second parameter represents the options. The allowed options can be found on the Mozilla Developer Network. As you can see in the example the main advantage is that you do need to worry about the representation of the date format in the different languages and that you do not need to add manually a leading zero if necessary.

The same applies to the Number object.

Function Purpose
Number.prototype.toLocaleString() returns a string with a language sensitive representation of this number.

You can use it as follow

	var number = 3600;
	number.toLocaleString('en');
	// 3,600
	number.toLocaleString('de');
	// 3.600
	number.toLocaleString('en', {
		style: 'currency',
		currency: 'USD'
	});
	// $3,600