$string =~ s/([^a-zA-Z0-9])/'&#'.unpack('U0U*',$1).';'/eg;

##</code><code>##

use HTML::Entites qw( encode_entities );
$string = encode_entities($string);

##</code><code>##

use Encode qw( encode );
$string = encode('US-ASCII', $string, Encode::FB_HTMLCREF);

##</code><code>##

use Encode qw( from_to );

sub unicode_decode
{
  my $string = shift;
  from_to($string, 'UTF-8', 'US-ASCII', Encode::FB_HTMLCREF);
  return($string);
}