use HTML::TreeBuilder;

  sub strip_a_elements
  {
    my( $html, $preserve_formatting ) = @_;
    my $t = HTML::TreeBuilder->new;
    if ( $preserve_formatting )
    {
      $t->no_space_compacting(1);
      $t->ignore_ignorable_whitespace(0);
      $t->store_comments(1);
      $t->store_declarations(1);
      $t->store_pis(1);
    }
    $t->parse( $html )->eof;
    # we've parsed; now do the desired transformation:
    $_->replace_with_content for $t->find_by_tag_name('a');
    # and return the resulting hunk of html:
    $t->as_HTML
  }