Andrew Pollack's Blog

Technology, Family, Entertainment, Politics, and Random Noise

- CORRECTION - Having just wasted a good bit of the afternoon, here's a technote on setting cookie expiration dates for IE

By Andrew Pollack on 02/24/2008 at 12:41 PM EST

* Corrected on Feb 24.

Many of you super JavaScript programmers already know this, but since I didn't have it quite right I thought I'd post it here so that if someone else is searching for information they'll have an easier time of it.

When you set a cookie in JavaScript, you make it 'permanent' (make it last through browser restarts) by setting a parameter called "expires". There are web pages all over the place that will tell you about lots of different formats you can set that expiration date in. Many of them work for Mozilla and other other browsers.

For Internet Explorer -- particularly for Internet Explorer version 7 -- there is only one format that actually works in a reliable way. There are technotes that claim you can use "14 day" or "1 year" or "2 hours". There are technotes out there that claim you can use a unix numeric time value (the number of seconds since 1/1/1970). While these may work for other browsers, you will waste your time if you try them with IE7. Worse, it will not give you any error or indication that it failed. It simply won't keep the cookie if you restart the browser.

Yes, sometimes other formats work. Not reliably however. The "Correct" format* according to Microsoft is:


The values are as follows:

DAY = Mon, Tue, Wed, Thu, Fri, Sat, Sun
MON = A Three Letter Version of the Month (Jan, Feb, ...)
DD = A two digit number representing the Day
YYYY = A four digit number representing the Year
HH = A two digit number representing the hour, in 24 hour time format.
MM = A two digit number representing the Minute
SS = A two digit number representing the Second
GMT = Always set dates in GMT time, and include GMT on the string

For all numeric values, you MUST use both digits. Pad with a leading zero as needed

* I have noted that if you tell Microsoft's JavaScript implementation to output Date.toGMTString() you get this in the same format but without dashes between the date components:


Since the common JavaScript way to do this is to use a data object this way, it is safe to assume this is also supported. In my testing, it does work.

There are  - loading -  comments....

Other Recent Stories...

  1. 01/26/2023Better Running VirtualBox or VMWARE Virtual Machines on Windows 10+ Forgive me, Reader, for I have sinned. I has been nearly 3 years since my last blog entry. The truth is, I haven't had much to say that was worthy of more than a basic social media post -- until today. For my current work, I was assigned a new laptop. It's a real powerhouse machine with 14 processor cores and 64 gigs of ram. It should be perfect for running my development environment in a virtual machine, but it wasn't. VirtualBox was barely starting, and no matter how many features I turned off, it could ...... 
  2. 04/04/2020How many Ventilators for the price of those tanks the Pentagon didn't even want?This goes WAY beyond Trump or Obama. This is decades of poor planning and poor use of funds. Certainly it should have been addressed in the Trump, Obama, Bush, Clinton, Bush, and Reagan administrations -- all of which were well aware of the implications of a pandemic. I want a military prepared to help us, not just hurt other people. As an American I expect that with the ridiculous funding of our military might, we are prepared for damn near everything. Not just killing people and breaking things, but ...... 
  3. 01/28/2020Copyright Troll WarningThere's a copyright troll firm that has automated reverse-image searches and goes around looking for any posted images that they can make a quick copyright claim on. This is not quite a scam because it's technically legal, but it's run very much like a scam. This company works with a few "clients" that have vast repositories of copyrighted images. The trolls do a reverse web search on those images looking for hits. When they find one on a site that looks like someone they can scare, they work it like ...... 
  4. 03/26/2019Undestanding how OAUTH scopes will bring the concept of APPS to your Domino server 
  5. 02/05/2019Toro Yard Equipment - Not really a premium brand as far as I am concerned 
  6. 10/08/2018Will you be at the NYC Launch Event for HCL Domino v10 -- Find me! 
  7. 09/04/2018With two big projects on hold, I suddenly find myself very available for new short and long term projects.  
  8. 07/13/2018Who is HCL and why is it a good thing that they are now the ones behind Notes and Domino? 
  9. 03/21/2018Domino Apps on IOS is a Game Changer. Quit holding back. 
  10. 02/15/2018Andrew’s Proposed Gun Laws 
Click here for more articles.....

pen icon Comment Entry
Your Name
*Your Email
* Your email address is required, but not displayed.
Your thoughts....
Remember Me  

Please wait while your document is saved.