Save JSON Result from WebService into variables

Hello Guys. I am new to jQuery and would like to know how I can save the result of a WebService call into variables using jQuery. The WebService returns an Object of type CProduct and it queries the database and returns the object in response.d because I can view the result in FireBug but I am stuck after that point.

$("#btnLookup").click (function(event) {

var mCode = $("#item_code").val();
var mData = "{ 'vCode' : '" + mCode + "' }";

$.ajax( {
           type: "POST" ,
           url: "ProductService.asmx/getSingleProduct" ,
           data: mData ,
           contentType: "application/json; charset=utf-8" ,
   ...