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Personal blog of the one called Alex Gorbatchev, from Toronto, Canada.

JavaScript cookies library

Posted on June 2nd, 2007 by Alex Gorbatchev. In JavaScript. 5 comments!

I was shocked to discover that finding a JavaScript library to work with browser cookies isn’t as easy as I expected. So I’m rolling my own solution.

This code allows to access cookies directly by name or an alias.

var Cookies = {
	aliases: {},

	alias: function(alias, name, defaultValue)
	{
		Cookies.aliases[alias] = name;

		Cookies[alias] = function(value, days)
		{
			if(value == null)
				return Cookies.get(name, defaultValue);
			else
				Cookies.set(name, value, days);
		}
	},

	set: function(name, value, days)
	{
		name = Cookies.aliases[name] || name;

		var expires = '';

		if(!isNaN(days))
		{
			var date = new Date();
			date.setTime(date.getTime() + days * 24 * 60 * 60 * 1000);
			expires = "; expires=" + date.toGMTString();
		}

		document.cookie = name + "=" + escape(value) + expires + "; path=/";
	},

	get: function(name, defaultValue)
	{
		name = Cookies.aliases[name] || name;

		var regex = new RegExp(name + "s*=s*(.*?)(;|$)");
		var cookies = document.cookie.toString();
		var match = cookies.match(regex);

		if(match)
			return unescape(match[1]);

		return defaultValue;
	},

	erase: function(name)
	{
		Cookies.set(name, '', -1);
	}
}

// Create an alias for a cookie named 'a'
Cookies.alias('greeting', 'a', 0);

// Set the value
Cookies.greeting(parseInt(Cookies.greeting()) + 1);

// Display the value
alert(
	Cookies.greeting() + 'n' +
	Cookies.get('a') + 'n' +
	Cookies.get('greeting')
);
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5 comments.

  1. Agreed it is surprising! Works very well, even in Safari. Thanks for stepping up to the plate and hitting the home run!

  2. Thanks a lot. This code came in very handy!

  3. Jim

    Hi Alex! I wrote a JavaScript Cookie Handling Library in Nov of 2005 for the same reason that you wrote one–I was dissatisfied with JavaScript’s capabilities in this area and I didn’t like a lot of what I was finding written by other people (which was very little). I found yours today when I was googling to see where my library fell in the search rankings for the terms ‘JavaScript Cookie Library’.

    While I won’t link to my library from here without an invitation (as I do not want to spam) I just wanted to say that I like yours a lot. Some specific things in yours are certainly better than my own, though I do have some things in mine that I like better than yours. Specifically, I like that yours uses regular expression to find the value within the document.cookie string as I am using some long and elementary string position method to find the cookie/value. I also like the real OOP feel that yours has. Mine is written in an OOP manner, bu still has a bit of a procedural feel to it. However, in mine I have tried to account for every parameter that I believe the developer should be able to control when setting a cookie including path, domain, and HTTPS only.

    I was also wondering what benefit you find in allowing for aliases? I am not critiquing it–just wondering.

    Have you released yours under any specific license? I’d love to roll some concepts from yours into mine, but don’t want to be a thief. If you’d like to take a look at mine and offer some critique on it, I can email you a link or post it here in the comments. Just let me know.

    Thanks a lot,
    Jim

  4. Sujoy Roy

    Though this post is pretty much old. But i can help to bless Alex. Simply fantastic.

    Live logn
    Sujoy

  5. Robert

    Hi,

    this seems not to work in Chrome … just FYI. :)

    Cheers!

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