What you're encountering is a caching problem.

Either your browser, the webserver, or something in-between (like a caching HTTP proxy) is caching the page. When it sees your next request it thinks "oh, I've already gotten this page, so I'll ust the one I got before and stored". What you need to do is put some HTTP headerers on your page so it isn't cached. Setting your HTTP headers as follows shout make pretty sure that it won't be cached.

Content-type: text/html
Expires: Mon, 26 Jul 1997 05:00:00 GMT
Cache-Control: no-cache, must-revalidate
Pragma: no-cache
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