php___ Expired Header Expires

Proxy, the browser caches the document until it expires, the reload of the cached document does not contact the server, and an attempt to obtain an outdated document contacts the server

Set the expiration time for a document

Header ("expires:sun,27 Mar 16:38:00 GMT"),//GMT Greenwich Mean Time

Expires after x hours

$now =time ();

$then =gmstrftime ("%a,%d%b%Y%h:%m:%s GMT", $now +60*60*3);//Expires after 3 hours

Header ("expires:{$then}");

Never expire

$now =time ();

$then =gmstrftime ("%a,%d%b%Y%h:%m:%s GMT", $now +365*86440);

Header ("expires:{$then}");

php___ Expired Header Expires