Programmers Stack Exchange is a question and answer site for professional programmers interested in conceptual questions about software development. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've noticed that July 26th (my birthday) is used really often in various PHP examples related to preventing http caching using Expires header, like:

What's special in that date?

share|improve this question
Interestingly it's not the example date on either the HTTP/1.0 or the HTTP/1.1 RFCs, both use Thu, 01 Dec 1994 16:00:00 GMT (...and yes, it was a Thursday ;). – Yannis Sep 13 '12 at 3:52
From looking around, '7/26/97' is whats in the PHP docs for header output. Have no idea if thats the cause (people copy/pasting), or just another case. – GrandmasterB Sep 13 '12 at 4:00
Could it be Sysadmin Day? It fell on July 26th in 2002 (and also in 1996, if Sysadmin Day had been celebrated in that year already... which AFAIK was not the case). – Péter Török Sep 13 '12 at 7:02
up vote 10 down vote accepted

Probably somebody did that as an example of a cache expires a long time ago and then everybody copied it. Interestingly it's often expressed as "Mon, 26 July 1997", but the actual date occurred on a Saturday. It's not that interesting in terms of UTC seconds (seconds since 1970) since it is 869893200. Maybe it's just an example of CTRL-C/CTRL-V coding?

share|improve this answer

Only thing I could find was the release of Mac OS 8. Not related to CSS release dates, HTML, XML, PHP, Javascript, Internet Explorer, Nescape Navigator, Apache Foundation, MySQL, or anything else relevant I could wrack my brain for. I suspect it's probably someone's kid's birthday or anniversary or something. In short, it's a coincidence.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.