setting values for nested JSON in Jquery

I have a Json which looks like following

{
    "Market": 0,
    "Marketer": null,
    "Notes": null,
    "SalesC开发者_StackOverflow社区hannel": null,
    "ServiceLocations": [
        {
            "ExtensionData": null,
            "AdminFee": 0,
            "CommodityType": 0,
            "ContractType": 0,
            "Payment": {
                "ExtensionData": null,
                "BankAccountNumber": null,
                "BankAccountType": 0,
                "BankRoutingNumber": null,
                "CardType": 0,
                "CreditCardExpirationDate": "/Date(-62135575200000)/",
                "CreditCardNumber": null,
                "CreditCardReferenceID": null,
                "CreditCardSecurityCode": null,
                "PaymentAddress1": null,
                "PaymentAddress2": null,
                "PaymentAmount": 0,
                "PaymentCity": null,
                "PaymentCounty": null,
                "PaymentFirstName": null,
                "PaymentLastName": null,
                "PaymentPhone": null,
                "PaymentState": null,
                "PaymentType": 0,
                "PaymentZip": null
            },
            "ProductID": null,
            "PromoCode": null,
            "Rate": 0,
            "RateSchedule": null,
            "ServiceAddress1": null,
            "ServiceAddress2": null,
            "ServiceCity": null
        }
    ],
    "SocialSecurityNumber": null,
    "SubAgent": null,
    "Login": null
}

I want to dynamically loop through the the JSON and set the values of each key value pairs. if the value is present set the value but if the value is not present then leave it as is.

im doing something like this because this doesnt seem to work

$.getJSON("data.js",function buildjson(json){
                myJSONObject = json;
                        for (var key in myJSONObject) {
                                    if(myJSONObject.hasOwnProperty(key)){
                                    if(typeof(myJSONObject[key]) === 'object')
                                    {
                                    newJson(myJSONObject[key]);
                                    }

                                    if($("#main").find(":input[name="+key+"]") != "") {
                                    modifyJson(key,myJSONObject[key]);
                                    }
                                    else{
                                    setData(key,myJSONObject[key]);
                                    }
                                    $("#keylist").append(key+":"+myJSONObject[key]+"<br />");
                                    //newJson(myJSONObject[key]);
                                }
                    }
                function newJson(myJSONObject) {
                    for (var key in myJSONObject) {
                                        if(myJSONObject.hasOwnProperty(key)){
                                        modifyJson(key,myJSONObject[key]);
                                        newJson(myJSONObject[key]);
                                    }
                        }
        }
        function setData(path, value) {
    if (path.indexOf('.') != -1) {
        path = path.split('.');
        for (var i = 0, l = path.length; i < l; i++) {
            if (typeof(data[path[i]]) === 'object') {
                continue;
            } else {
                data[path[i - 1]][path[i]] = value;
            }
        }
    } else {
        data[path] = value;
    }
};

            function modifyJson(key,value) {
                var theValue = value;
                //$("#keylist1").append(key+":"+theValue+"<br />");
                if($("#main").find(":input[name="+key+"]")) {
                    theValue = $(":input[name="+key+"]").val();
                    setData(key,theValue);
                }
            }

    });

    }

What modification do i need to do?

You have a trailing comma after "ServiceCity": null which is causing an invalid JSON object.