Value is lost after ajax call

Question

When ajax compass with the value new prices you can see it it the succes function.

But if you want to see the value under the ajax function new_prices is undefined ??

How is this possible?

var new_prices;

         $.ajax({
            type: "POST",
            url: "/spares/admin/getKoersBetweenDate/",
            dataType: "json",
            data: "valutaId=" + valutaId + "&datum=" + date_added,
            success: function(response){
                  var new_price = price_ps / response.valuta[0].koers;
                   var total = new_price;
                   new_prices = total;

            }
        });
         console.log(new_prices);