<?php

exec('/usr/sbin/list_members list', $addresses);

echo 'Wer hat Geburtstag?<br/>';
echo '<select id="mail-select"><br/>';
foreach ($addresses as &$addr){
    echo '<option value="' . $addr . '">' . $addr . '</option>';
}
echo '</select><br/><br/>';
echo '<input type="button" onclick="selectedMail();" value="Mail öffnen"></input>';
?>

<script type="text/javascript">
 function sendMail(addresses, bdayAddr){
     var bdayPerson = bdayAddr.substr(0, bdayAddr.indexOf('@'));
     var toAddr = addresses.join(';');
     var subject = 'Geheime Geburtstagsmail für ' + bdayPerson;
     var message = 'Hallo ihr!\n\n'+bdayPerson+' hat bald Geburtstag!';
     
     window.location.href = "mailto:"+
                            encodeURI(toAddr) +
                            "?subject=" +
                            encodeURIComponent(subject) +
                            "&body=" +
                            encodeURIComponent(message);
 }
 function selectedMail(){
     var mailSelect = document.getElementById('mail-select');
     var options = mailSelect.getElementsByTagName('option');
     var mailAddresses = [];
     var selectedIndex
     for (var i=0; i<options.length; i++){
         var option = options[i];
         mailAddresses.push( option.value );
         if ( option.selected ){
             selectedIndex = i;
         }
     }

     var selectedAddress = mailAddresses[selectedIndex];
     mailAddresses.splice(selectedIndex,1);
     sendMail(mailAddresses, selectedAddress);
     
     console.log(mailAddresses);
     console.log(selectedAddress)
 } 
</script>