Stop browser caching and/or forcing refresh

[Eiolon]

I have an event registration form that I created which only allows 20 signups.  I created a script to query the database and see how many entries there are.  If there are 20 entries, don't show the sign-up link.  I did the same with the actual registration page incase they want to try the link to the form directly.

Now this works fine and all but the browser cache is getting in the way.  After I register someone and am taken back to the list of participants it won't show the one I just added until I refresh.  This means if I have added the 20th person I can still add a 21st which would mean overbooking the event.

So is there a way to force the browser (IE6) to refresh or to stop the caching.  I have tried the META tags for no-cache and pragma.  I can't use the META tag for refresh because it will just refresh every second and not just do it once.  Thanks for your help.

[fert]

I believe this will work
[code]
header("Cache: no-cache");
[/code]