+sub no_cache($)
+{
+my($self)=@_;
+
+ header("Expires"=>"Mon, 26 Jul 1997 05:00:00 GMT"); # date in the past
+ header("Last-Modified"=>strftime("%a, %d %b %Y %H:%M:%S GMT",gmtime())); # always modified
+ header("Cache-Control"=>"no-cache, must-revalidate"); # HTTP/1.1
+ header("Pragma"=>"no-cache"); # HTTP/1.0
+}
+