Ciao, ci sono riuscitaa
naturalmente ho cambiato strategia. Prima cosa fondamentale ho messo l'incremento della quantià al posto della select.....

metto il codice, servisse a qualcuno
Codice PHP:
                        <?php
                            if (contaArticoli()==0) {
                                echo '<h1>Il tuo carrello è vuoto</h1>';
                            }
                            else {
                                $i=0;
                                $boundary = md5(uniqid(microtime()));
                                $query_cart = mysql_query("SELECT *,`".$_SESSION['temp_tablename']."`.`id` AS `id_elem` FROM `".$_SESSION['temp_tablename']."` JOIN `prodotti` ON `".$_SESSION['temp_tablename']."`.`id_prod`=`prodotti`.`id` ORDER BY `id_elem` DESC");
                                while ($row_prodCart = mysql_fetch_array($query_cart)) {
                                    echo '
                        <div class="row" data-id="'.$row_prodCart['id_elem'].'" id="rec'.$row_prodCart['id_elem'].'">
                            <div class="col-md-3 col-xs-12">
                                <div class="portfolio-thumb">
                                    <img src="public/amministrazione/img/prodotti/'.$row_prodCart['img'].'" alt="'.$row_prodCart['prodotto'].'" class="img-thumbnail" />
                                </div> <!-- /.portfolio-thumb -->
                            </div> <!-- /.col-md-3 -->
                            <div class="col-md-9 col-xs-12">
                                <div class="portfolio-info">
                                    <h1>'.$row_prodCart['prodotto'].'</h1>
                                    <p>Prezzo unitario <span class="przUnix1">&euro; '.$row_prodCart['prezzo'].'</span></p>
                                        <button class="less">-</button>
                                        <input value="1" type="text" data-rel="'.$row_prodCart['prezzo'].'" readonly>
                                        <button class="more">+</button>
                                    <label>Totale &euro; <span class="parzial">'.$row_prodCart['prezzo'].'</span></label>
                                    <label class="btnCart fa-remove">elimina <i class="fa fa-remove"></i></label>
                                </div> <!-- /.portfolio-thumb -->
                            </div> <!-- /.col-md-3 -->
                        </div> <!-- /.row -->
                                    ';
                                }
                            }
                            ?>
                            <div id="totCart">qui: </div>
e questo è javascript
codice HTML:
<script>
function totCart(){
var sum = 0;
$('.portfolio-info .parzial').each(function() {
        value = 0;
        var value = $(this).text();
        if(!isNaN(value) && value.length != 0) {
            sum += parseFloat(value);

        }
    $('#totCart').text(sum.toFixed(2));
});
}
function quantityWidget(){
    var currval;
    $(".portfolio-info .less").click(function(){
        currval = parseInt($(this).parent().find("input").val());
        var money = $(this).parent().find("input").attr("data-rel");    
        if (currval > 0){
        $(this).parent().find("input").val((currval-1));
        var currqty = currval-1;
        var total = new Number(currqty * money);
        total = total.toFixed(2);
        $(this).parent().find(".parzial").text(total);
        totCart();
        }
    });
    $(".portfolio-info .more").click(function(){
        currval = parseInt($(this).parent().find("input").val());    
        var money = $(this).parent().find("input").attr("data-rel");    
        $(this).parent().find("input").val((currval+1));
        var currqty = currval+1;
        var total = new Number(currqty * money);
        total = total.toFixed(2);
        $(this).parent().find(".parzial").text(total);
        totCart();
    });
}

$(function(){
    quantityWidget();
    totCart();
});
</script>