`HTML::Parser`

For example, GetLinks::start overrides HTML::Parser::start

        package GetLinks;
        use base 'HTML::Parser';

        sub start {
          my ($self, $tagname, $attr, $attrseq, $origtext) = @_;
          if ($tagname eq 'a' && exists $attr->{href}) {
            push @{$parser->{links}}, $attr->{href};
          }
        }

For a tag like this:

        <IMG src="arrow.gif" ALT='-->' height=54 width=30>

$tagname:

        'img'

$attr:

        { alt => '-->', height => 54, src => 'arrow.gif', width => 30 }

Similarly, for <A HREF="http://www.perl.com/">:

        $tagname        a
        $attr           { href => 'http://www.perl.com/' }