package HTML::Sanitizer;
require HTML::Filter;
@ISA=qw(HTML::Filter);

my $data='';

my %keep=(
  a => 1,
  p => 1,
  img => 1
);

sub output{
  my $self=shift;
  my $d=$_[0];
  if($d=~/\<\s*\/?\s*(\w+)/){
    if(exists $keep{lc($1)}){
      $data.=$d;
    }
  }else{
    $data.=$d;
  }
}

my $p=HTML::Sanitizer->new();
$p->parse_file("index.html");

print $data;