No, not about formatting the string, I just want to know the actual offset of the client's computer compared with UTC. It seems our website knows that already but it isn't updated if I change my computer's time zone.

EDIT: Maybe it's cached and gets corrected after a while, I don't know. I suppose it's a bit complicated because the php is of course running on the server but we are talking about the client computer's time zone, so perhaps that isn't readily available on the server.

OK I think I'm starting to get the picture, it must be updated by the ajax request, as Flame said though that's not something I am familiar with yet. I suppose there is a mechanism for the client computer to inform the web server of its timezone, but we don't want to do that all the time.

EDIT2: Maybe it's not a bug at all. Maybe LFS website just isn't very quick to get the timezone right if the client adjusts their time zone. But it would be good to know if it eventually gets corrected.

I've added a "Time zone" display in account settings: https://www.lfs.net/account/settings

You can see what the server thinks your offset is.

The result is:
- if I change my time zone, that offset is unaffected (even refresh page)
- exit the browser and go back to that page, offset is still at old time zone
- log out from LFS.net and lock back in, my new time zone offset is acquired

As far as I can tell, this only affects calendar display and something to do with poll expiry times, so I think it's not worth further investigation.