Making a server ignore post data the second time?

Factual Questions
1

I’m using IIS/PHP to build a website, and I’m trying to figure out a way that it won’t ask people to resubmit post data if they press the back button (or refresh) on their browser. I’m relatively sure (and will be checking as I submit this post) that the SDMB doesn’t pop up the one message box, so it does seem to be possible.

Anyone know what it is?

2

It has to do with the way the app is written – typically what you can do is after your server processes the POST, immediately do a redirect (e.g., in the case of vBulletin, it can “redirect” you to the post you just made). This will result in the user’s browser performing a GET, which you can click back onto without any popup.