Pragma HTTP Headers

Many people believe that assigning a Pragma: no-cache HTTP header to an object will make it uncacheable. This is not necessarily true; the HTTP specification does not set any guidelines for Pragma response headers; instead, Pragma request headers (the headers that the browser sends to a server) are discussed. Although a few caches may honor this header, the majority won't, and it won't have any effect. The following headers must be used instead.