sub validate
{
    my $text = shift;
    my $new_text = '';
    my %is_approved = ();
    my @approved_tags = (
        'a',
        'p', 'br',
        'b', 'i', 'strong',
        'tt', 'small', 'strike',
        's', 'u', 'sub', 'sup',
        'blockquote',
        'table', 'th', 'tr', 'td',
        'caption', 'thead', 'tfoot', 
        'tbody', 'colgroup',
        'dl', 'dt', 'dd', 
        'ul', 'li', 'ol',
    );    
    foreach( @approved_tags ) { $is_approved{ $_ } = 1 }

    my $validator = HTML::Parser->new(
        start_h => [sub 
        { 
            my $self = shift;
            my ($tagname, $attr, $origtext) = @_;
            
            $new_text .= $origtext if ($is_approved{ $tagname });
        }, "self, tagname, attr, text"],
        
        end_h => [sub 
        { 
            my $self = shift;
            my ($tagname) = @_;
            
            $new_text .= "</$tagname>" if ($is_approved{ $tagname }); 
+               
        }, "self, tagname"],

        text_h => [sub 
        { 
            my $self = shift;
            my ($origtext) = @_;
            
            $new_text .= $origtext;
        }, "self, text"]
    );
    
    $validator->parse( $text );
    return $new_text;
}
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