Convert javascript date to c# datetime and timespan

 DateTime startDate = Convert.ToDateTime(postData.StartDate);
                DateTime endDate = Convert.ToDateTime(postData.EndDate);
                DateTime enrollEndDate = Convert.ToDateTime(postData.EnrollEndDate);

                DateTime startTimeDate = Convert.ToDateTime(postData.StartTime);
                DateTime endTimeDate = Convert.ToDateTime(postData.EndTime);

                TimeSpan startTime = startTimeDate.TimeOfDay;
                TimeSpan endTime = endTimeDate.TimeOfDay;