use strict;
use warnings;
use HTML::TokeParser::Simple;
use Data::Dumper;

my $parser = HTML::TokeParser::Simple->new('foo.html');
my $level  = 0;
my @div;

while ( my $token = $parser->get_token ) {
   if ($token->is_start_tag('div')) {
      push @{$div[$level]}, $token->return_attr->{id}; 
      $level++;
   } elsif ($token->is_end_tag('div')) {
      $level--;
   }
}

# print all div's found
for my $row (@div) {
   print "level ", ++$level, " div's:\n";
   print "\t$_\n" for @{$row};
}

# print first outer level div found
print "the first div found had id '", $div[0][0], "'\n";