use HTML::Parser;

my (%tags_1) = map { (lc($_), 1) } qw ( A B BR P );

sub HTMLSafeContent
{
             my ($content, $tags) = @_;
             my ($safe_content);

             my ($Tag) = sub
             {
                     my ($tagname, $attr, $offset, $length) = @_;

                     if ($tags->{$tagname})
                     {
                             $safe_content .= substr($content,$offset,$length);
                     }
             };

             my ($Text) = sub
             {
                     my ($text) = @_;

                     $safe_content .= $text;
                     # Or, perhaps:
                     #   $safe_content .= URLIfy($text);
             };

             my ($hp) = new HTML::Parser (
                                     api_version   => 3,
                                     start_h => [ $Tag,  'tagname,attr,offset,length' ],
                                     end_h   => [ $Tag,  'tagname,attr,offset,length' ],
                                     text_h  => [ $Text, 'dtext' ],
                             );

             $hp->parse($content);

             return $safe_content;
     }

     # Using it:

     # Load content into $some_content

     print HTMLSafeContent ($some_content, \%tags_1);