Possible Duplicate:
Using <meta> tags to turn off caching in all browsers?
I am just curious as one html tag it's efficient for no-cache.
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
or
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
User agents are not required to support meta data mechanisms:
http://www.w3.org/TR/html401/struct/global.html#h-7.4.4.1
Using one or both shouldn't cause problems, but it would probably be more effective to send a NO-CACHE directive over HTTP.