You need to reset the caching headers for that files:
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
header("Last-Modified: Tue, 15 Nov 1794 12:45:26 GMT");
Make sure your webserver is not overwriting the caching headers for that files.
You might also want to check why the webserver wants the browser to store dynamic content in the cache (eg. why it caches .php-files).