Just as a proxy server caches pages, WAP devices generally come with some memory to act as a cache. Remember that bandwidth is still a limitation for current WAP devices, so caching WML pages can generally led to improved performance.
While a cache memory helps to load a page that has been loaded previously without making a connection to the origin server, it is a nuisance where time-sensitive pages are concerned. Pages like stock information, weather reports, and online ticketing systems are highly time-sensitive.
By default, WML pages are cached. To force a WML deck to expire immediately after it has been received, use the Response.Expires property in your time sensitive WML pages:
<% response.setHeader("Cache-Control","no-cache"); response.setHeader("Pragma","no-cache"); response.setDateHeader ("Expires", 0); %> <?xml version="1.0"?> (Static WML page content)
<?php header("Cache-Control: no-cache"); header("Pragma: no-cache"); header("Expires: Thu, 29 Oct 1998 17:04:19 GMT"); ?> <?xml version="1.0"?> (Static WML page content)