use HTML::Parser;

sub handle_img {
    my $attr = shift;
    if ($attr->{"src"} eq "perlmonks") {
        print "Oh, a monk\n";
    } else {
        print "Who are you?\n";
    }
}

sub start {

    my ($self, $tagname, $attr) = @_;
    if (lc($tagname) eq "img") {
        handle_img($attr);
    }
}

$p = HTML::Parser->new(start_h => [\&start, "self, tagname, attr"]);
$p->parse_file("a.html");