$browser->follow_link( text_regex => qr/Download as TAB/i );
if ( my $filename = $browser->res->filename )
{
    die "file already exists [$filename]" if -e $filename;
    print STDERR "Saving downloaded file to [$filename]\n";
    open my $fh, ">", $filename;
    print $fh $browser->content;
    close $fh;
}