Hi Tom,
In html, there is no "interactivity" possible; we have to rely on javascript for that!
But javascript doen't work on files (on disk), we have to extend it with Ajax or others,
Finally, we have to think performance, as it is not a good idea to run a script each
and every time a visitor see your index page (as example)... for something occurs
only 4 times a year!
But, one thing I think of is a Cron job, I don't know more about that to see if we can
specify a date! Cron is a "scheduler" that can do reapeated task; at "5 min" interval,
each hour, each thursday night... but I don't know for a specific date.
Could be something to check, usualy every server have Cron
Jacques