$(document).ready(function () {

   var updatePrice = function (){
      $('#customPrice').load("./get_price.cfm", 
         {
            Quantity: $('#qty').val(), 
            BasePrice: $('#BasePrice').val(), 
            weekprice: $('#Week').val()
         }, function () {
   	      $('#customPrice').show("slow");
         }
      );
   }

   $("#Week").change(updatePrice).change();
   $("#qty").keyup(updatePrice);

});