JavaScriptSerializer - Invalid JSON primitive: object.

function tableToJson(activeTab) {
            var data = [];

            // first row needs to be headers
            var headers = [];
            var header_length = $('#grd_'+(activeTab+1)+' tbody th').length;
            for (var i = 0; i < header_length; i++) {
                var header_name = $('#grd_' + (activeTab + 1) + ' tbody th')[i].innerHTML;
                switch (header_name) {
                    case "Your Type":
                        headers[i] = "YourType";
                        break;
                    case "Code":
                        headers[i] = "YourCode";
                        break;
                    case "Your Type":
                        headers[i] = "YourType";
                        break;
                    case "Your life":
                        headers[i] = "YourLife";
                        break;
                    case "Period":
                        headers[i] = "YourPeriod";
                        break;
                    case "Qualifying Cost":
                        headers[i] = "OriginalCost";
                        break;
                    case "B/F Cost":
                        headers[i] = "Cost";
                        break;
                    case "Rate%":
                        headers[i] = "Rate%";
                        break;
                    case "Your Amount":
                        headers[i] = "YourRate";
                        break;
                    case "Your Amount":
                        headers[i] = "YourAmount";
                        break;
                    case "Your Carrying Amount":
                        headers[i] = "YourCarryingAmount";
                        break;
                    case "Last Date":
                        headers[i] = "YourGeneratedDate";
                        break;
                    default:
                    break;
                 }
            }

            // go through cells
            var totalRowData_length = $('#grd_' + (activeTab + 1) + ' tbody tr').length;
            for (var i = 1; i < totalRowData_length; i++) {

                var tableRow = $('#grd_' + (activeTab + 1) + ' tbody tr')[i]
                var tableRow_length = $('#grd_' + (activeTab + 1) + ' tbody tr')[i].cells.length;
                var rowData = {};

                for (var j = 0; j < tableRow_length; j++)
                {
                    var dt = $('#grd_' + (activeTab + 1) + ' tbody tr')[i].cells[j].innerHTML;
                    if (dt.indexOf('INPUT') != -1) {
                        var mypattern = "value=\'?[0-9]*\.?[0-9]*\'?";
                        var myRegExp = new RegExp('(' + mypattern + ')', "g");
                        var result = dt.match(myRegExp);
                        var length = result.length;
                        if (result.length > 0)
                            dt = result[0].replace("value=", "");
                        else
                            dt = "0.00";
                    }
                    rowData[headers[j]] = dt;
                }

                data.push(rowData);
            }

            return data;
        }

Is above valid Json ? How do I check whether it is valid? 

After converted tables to Json array over clientside script, I got Invalid Json primitive error when passing the following code. 

JavaScriptSerializer serializer = new JavaScriptSerializer();
List<ABC> lstABC = serializer.Deserialize<List<ABC>>("{"+((TextBox)Master.FindControl("txtABCString")).Text+"}");

What are the possible matter that can cause this problem. I had changed the header name to be exacted with ABC class. I am not sure what else could be the cause. There are date field in the class. Should I convert the date field to DateTime? But I do the conversion over client side.. 

After adding the "{" "}" I got the error below instead. What is it about really? what is the member name regarding to?  

Invalid object passed in, member name expected. (1): {[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]}