Cookie expiration dates

Every so often, I’ll see a cookie request that has an expiration date that’s already past. Lots of times, the cookie looks like it’s for advertising anyway, and I don’t accept those anyway. 1-1-2000 and some date in 1969 are favorites from some sites (, for one). But I’ve been wondering: What’s the purpose/benefit of giving an expiration date that’s already in the past?

What does this mean?

I don’t think she’s talking chocolate chip, like I first thought.

Oh. Right. :smack:

Even once I’m on the right kind of cookies, though, I still don’t get the question.

Setting the expiration date to some time in the past is how a server “kills” a cookie. Typically the scenario is something like this:

  1. You access a site, and it sets a cookie called “foo” with some data and an expiration date in the future. (Or no expiration date, in which case it will be deleted at the end of the browser session if not before.)
  2. You access the site again, and your browser sends “foo” back to the server.
  3. The site no longer requires your browser to store the information in “foo”, and resets the cookie with an expiration date in the past.
  4. Your browser immediately deletes cookie “foo”.

Really? But sometimes these cookies that are being modified are already set to expire at the end of the session. And I have - after clicking OK before assimilating the information - gone into my cookie listings and found such cookies.

Assuming it works as it’s supposed to (according to your explanation), why would they bother to delete a cookie that is already going to disappear when I next reboot?? I guess I just don’t get it. :smack: But thanks. It’s good to know I don’t have to worry about them. :slight_smile:

twickster, I use Netscape 7.1 (Mozilla engine; same as Firefox). And I have it set to get approval on cookies (unless I explicitly grant the site “all cookies”). I just wanted to understand why some of them have expiration dates that are years old - long gone. :slight_smile: