How I can set "price" variable after ajax call?
here the code: 

```
                var price;
                var idProd = data.prodotto_id;

                var cb = function (o,s,r){

                    price = Ext.util.JSON.decode(r.responseText).price;
                    console.log(price);
                };
                    Ext.Ajax.request({
                        url : "index.php",
                        params : {
                            m : "Prodotti",
                            a : 'prod-price-byquantity',
                            idProd : idProd,
                            quantity: qta
                        },
                        callback : cb,
                        scope : this
                    });

                console.log(price);

```

In the last console.log(price) I see price as undefined