# be careful with this ... a fork is executed for every link found
use LWP::Simple;
use HTML::LinkExtractor;

my $link = HTML::LinkExtractor->new;

$link->parse(\*DATA);

my @href = map $_->{href}, grep { $_->{tag} eq 'a' } @{$link->links};

for (@href) {
   next if fork;
   my $valid = head($_) ? 'good' : 'bad';
   warn "$_ is $valid\n";
   exit;
}

__DATA__
<ul>
<li><a href="http://www.perlmonks.org">Perlmonks</a></li>
<li><a href="http://www.yahoo.com">Yahoo</a></li>
<li><a href="http://bad.link.number.one">Bad #1</a></li>
<li><a href="file://not.there"></a>Bad #2</li>
</ul>