Ok, taking just the first 2 points try this to see if I understand you correctly

#!/usr/bin/perl
use strict;
use CGI::Ajax;
use CGI;

my $cgi = new CGI();
my $pjx = new CGI::Ajax( 
  'function1' => \&myfunction1,
  'function2' => \&myfunction2,
#   'skip_header'   => 1 
);

print $pjx->build_html($cgi,\&main,
    {-charset=>'UTF-8', -expires=>'-1d'});
    
sub main {
   my $html = <<EOT;
  <HTML>
  <HEAD><title>CGI::Ajax Example</title></HEAD>
  <BODY> 
  <div id="div2_text">Chapter = </div> 
  
  BOOK
  <select id="select1" onchange="function1(['select1'],['div1_text'], 
+'POST'); "> 
    <option value="">Select Book</option>
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
  </select></br>

  CHAPTER
  <div id="div1_text"></div>
  
  </BODY>
  </HTML>
EOT
    return $html;
}

sub myfunction2 { return "Chapter = ".shift };
sub myfunction1 {
  my $book = shift;
  my @chap = (undef,['1A','1B','1C'],
  ['2A','2B','2C','2D'],['3A','3B']);
  my $option;
  for (@{$chap[$book]}){
    $option .= qq!<option value="$_">$_</option>!;
  } 
  return qq!
  <select id="select2" onchange="function2(['select2'],['div2_text'], 
+'POST'); "> 
    $option
  </select>!;  
};

[download]
poj

In reply to Re^3: Using CGI::Ajax for multiple form buttons/divs simultaneously by poj
in thread Using CGI::Ajax for multiple form buttons/divs simultaneously by Polyglot

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