Part of my website creates pdf files dynamically (using PHP) and displays them in a popup. Unfortunately, I have an issue which is due (I think) to local caching.
What happens is that the first time a page is called up, it works fine. If it is re-called fairly quickly, then you get an instant "page not available" error. The browser doesn't even appear to make the request to to server.
I suspect some sort of local caching issue and was wondering if anyone could tell me what header I need to send with the page to inform the browser that the page is not to be cached.