sub mod304{
	my $self = shift;
	my $lastmod = time2str($self->{lastmod});
	if( exists($ENV{HTTP_IF_MODIFIED_SINCE}) && ($lastmod eq $ENV{HTTP_IF_MODIFIED_SINCE}) ){
		return 'Status: 304 Not Modified';
	}
	else{
		return;
	}
}

# HTTP::Date::time2str, str2time

# in Richtung Webserver:
# print "Status: 304 Not Modified\n\n"; # Leerzeile!
# exit 0;