This uses HTML::TokeParser::Simple

#!/usr/local/bin/perl
use strict;
use warnings;
use HTML::TokeParser::Simple;

# load your html into a string
my $content = do{local $/;<DATA>};

my $p = HTML::TokeParser::Simple->new(\$content);
while (my $t = $p->get_tag(q{input})){
  my $name = $t->get_attr(q{name});
  my ($token) = $name =~ /^org\.somescript\.html\.(.*)$/;
  print $token; # prints TOKEN
}

__DATA__
<!-- lots of html -->
<input
  name="org.somescript.html.TOKEN"
  type="hidden"
  value="f152a40cd9234c57542ee5b0c057cb0b"
/>
<!-- lots more html -->
[download]

other html parsers are available