use HTML::TreeBuilder;

# TreeBulder-Objekt anlegen
my $tree = HTML::TreeBuilder-new();

# HTML-File einlesen
$tree->parse_file($filename);

# HTML aus String einlesen
$tree->parse($htmlinput);
# weitere Zeilen:  $tree->parse($htmlinput2);
$tree->eof();   # eingabe beendet

# Ausgabe
my $output = $tree->as_HTML();