@CrazyMerlinOct 20.2006 — #what you need cannot be done in javascript as it requires you to store a value of the last script execution when the script is not running.
to do this you need a system command to run. Talk to you ISP, netword manager, about setting up a cron job.
you can then have it run a script every 3 hours to make your necessary changes.
@CrazyMerlinOct 20.2006 — #np, cron (chronological) is a unix system command that executes scripts every x minutes.
so you just tell it what script to execute and when and it takes care of everything.
usually it is used for running cgi scripts, but you can get it to run a php script also, which basically means you can do anything.
if you have access to the server control panel where your files are, and the software running is CPanel, you will have a link to Cron Jobs.
if not, just ask your ISP/net tech guy how to set one up. If none of those are an option let me know how/where your files are and I'm sure we can figure something out.
if you are on a windows server there are also versions for that like CRONw or WinCron.