Citibank.com scraping: XYZ_Extra, XXX_Extra

citibank_extra.pl

    # Compute the values of the extra fields XXX_Extra and
    # XYZ_Extra. This requires munging some deliberately
    # obfuscated code.
    #
    # Sometimes XXX_Extra and XYZ_Extra aren't provided (hence the
    # "if"), in which case we don't need them.
    my %extra_fields;
    if ($body =~ m{
                <script \s type="text/javascript"> \x0d \x0a
                (function .+?)
                \x0a \x0a \x0d}xs)
       {msg 'Found script.';
        my @funs = split /\n/, $1;
        # There should be exactly 4 of these functions, or
        # something has changed server-side.
        @funs == 4 or die 'numcheck';
        my $fun = runsub
           {foreach (@funs)
               {/(\w+)='<input type="hidden"/ or die;
                my $varname = $1;
                /\.append\($varname\)/ or next;
                return $_;}
            die 'No active fun found';};
        $fun =~ /'([^']+)';if\([^)]+\).+?'(\d+)'/ or die;
        my ($initial, $offset) = ($1, $2);
        %extra_fields =
           (XYZ_Extra => $fun =~ /name=XYZ_Extra value=([^>]+)/,
            XXX_Extra => substr $initial, length($initial) - $offset);}
    else
       {msg 'No script.';}