use HTML::LinkExtor;
use LWP::Simple;

$base_url = shift;
$parser = HTML::LinkExtor->new(undef, $base_url);
$parser->parse(get($base_url))->eof;
@links = $parser->links;
foreach $linkarray (@links)
{
	@element = @$linkarray;
    $elt_type = shift @element;
	while (@element)
	{
		($attr_name, $attr_value) = splice(@element, 0 , 2);
		$seen{$attr_value}++;
	}
}

for (sort keys %seen) 
{
	print $_, "\n";
}