#!C:/Perl/bin/perl -w
use strict;
use CGI ':standard';

my $MAX = 10; # maximum in list
my %list = ();
my $confirm    = param('confirm');
my $Email_List = param('Email_List');

# extract email adressess between ()
while ( $Email_List =~ m/\(([^)]+)/g ){
  my $addr = $1;
  
  # remove spaces and any other cleaning here
  # assuming you don't have unusual addresses like
  # "Any Person"@somewhere.com
  $addr =~ s/ //g; 
  
  # check valadity
  if ( is_valid($addr) ){
    $list{$addr} = 'Not sent'; #  using key avoids duplicates
  }    
}

# check not too many
my $msg;
my $no = scalar(keys %list);
if ($no > $MAX){
  $msg = "ERROR - $no is too many to send";
} else {
  # send emails if confirm checked
  if ($confirm){
    for (keys %list){
      $list{$_} = send_to($_); # store result
    }
  }
}

# input form 
print header(), start_html;
print qq!<h4>Recipients (maximum $MAX)</h4>
<form action="" method="post">
<textarea cols="80" rows="20" name="Email_List">
$Email_List
</textarea><br/>
<br/>
Confirm<input name="confirm" type="checkbox"/>
<input type="submit" name="action" value="Send"/>
</form><br/>
<span style="background-color:#ffff00">$msg</span>!;