Differences

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+====== Hinting to Clients that a Resource Should Not be Cached ======
+Three main headers control caching whenever a client fetches a resource over HTTP:
+  * ''Cache-Control'' - client cache control, defined for HTTP1.1
+  * ''Pragma'' - client cache control, defined for HTTP1.0
+  * ''Expires'' - proxy cache control, defined for both HTTP1.1 and HTTP1.0
+For each of those protocols, the headers should reflect the values:
+  * ''Cache-Control'' -> ''no-cache, no-store, must-revalidate''
+  * ''Pragma'' -> ''no-cache''
+  * ''Expires'' -> ''0''
+Note that other values can be set, such as ''private'' that, per definition, may implicitly make the browser not cache a resource - however the meaning of ''private'' refers to the fact that the resource is intended for a single user and must not be cached by a shared cache (RFC2616 section 14.9.1) which is different from the meaning of "not caching the resource under any circumstance".