Posted by Lars Eighner on 07/08/07 16:23

In our last episode,
<16ed3bff4e.Kevin@talktalk.net>,
the lovely and talented Kevin Wells
broadcast on comp.lang.php:

> In message <1183764307.320942.152330@z28g2000prd.googlegroups.com>
> newbie <mitbbsmj@yahoo.com> wrote:

>>Hi,
>>
>>I wonder if it's possible to detect a user (the browser's) timezone
>>when he/she access my php file? I saw ppl suggesting using javascript
>>to collect that information. But I wonder if it's possible to do it
>>without the headache of javascript.
>>

> Would it not be possible to do this from their IP address?

You could probably beat outright guessing in that way, but there is no
reliable relationship between IP and geography, no necessary relationship
between the IP making the request and the user's actual IP at any given
moment, and again no necessary relationship between the user's actual IP at
any moment and geography.

You might get it right most of the time, but you will get it wrong a
significant part of the time, and in some cases you'll get it wrong in an
absurd way --- such as claiming the page was last updated some time in the
future.

--
Lars Eighner <http://larseighner.com/> <http://myspace.com/larseighner>
Countdown: 561 days to go.
Friends of Lizbeth: help replace failed a/c at Austin's no-kill shelter
<https://secure.groundspring.org/dn/index.php?aid=12349>

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