Hi every body, I use the following code to force expire some pages (method POST) when user clicks on Back button of IE. response.setHeader("Expires", "Thu, 19 Nov 1981 08:52:00 GMT"); response.setHeader("Cache-Control", "max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0"); response.setHeader("Pragma", "no-cache"); The problem is when I configures my browser to pass through a proxy (Squid), this code doesn't work. That means when user clicks on Back button, he will see the precedent page in the browser's history instead of the "Webpage has expired" error. Even when I configure Squid to disable cache, it doesn't work. Please help me out! Thank you very much, Quang