Auto-Updating a Database

[Anon]

Ok here is what I want to do.
I have a database with number values in it. Every 10 days at midnight, I want my script to grab the values out of the table, multiply it by a certain number and then insert the new values into the fields of the old numbers. I can take care of grabbing the numbers out, multiplying and reinserting the new numbers, but I don't know how to make my script run at midnight.
Is there a way to use date() or timestamp() or something to do this?
I can't use PERL or any other language other than PHP or HTML. I think that means that 'cron' or whatever is out.
I searched the forum and there was nothing that could help me.

[gljaber]

No Perl required, but it's either do it yourself at the right time, or have the computer do it for you at the right time (i.e. schedule it, 'cron' or 'at' or whatever)

glj

[Anon]

That really wasn't what I was looking for. I was wondering if anyone know the PHP code to do such a thing...