$/ = "----- PAGE SEPARATAAAR -----\n";
while (<>) {
    chomp;
    # $_ now contains the HTML page
}

##</code><code>##

my $page = '';
while (<>) {
    if ( /xxx PAGE BOUNDARY \d+ xxx/ ) {
        output( $page );
        $page = '';
        next;
    }
    $page .= $_;
}