// servlet
response.setHeader("progma", "no-cache"); // HTTP1.1
response.setHeader("Cache-Control", "no-cache"); // HTTP1.0
response.setDateHeader("Expires", 0); // prevents catching at proxy server

<!-- html -->
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">