Показать данные на карте jquery

[WebMethod]  
        public static string mapgriddata(string FID,string ObID)  
        {  
            try  
            {  
                string result = "";  
                FID = HttpContext.Current.Session["FID"].ToString();  
                ObID = HttpContext.Current.Session["ObID"].ToString();  
                Entities w = new Entities();  
List(spgetdata_ffid_Result) gt = w.spgetdata_ffid(FFID).ToList();  
                DataTable dt = new DataTable();  
                dt.Columns.Add("No", typeof(string));  
                dt.Columns.Add("Longitude", typeof(float));  
                dt.Columns.Add("Latitude", typeof(float));  
              
               
                foreach (var t in gt)  
                {  
                      
                    dt.Rows.Add(t.No, t.Longitude, t.Latitude); 
t.No = HttpContext.Current.Session["No"].ToString();  
t.Latitude = Convert.ToSingle(HttpContext.Current.Session["Latitude"]);  
t.Longitude = Convert.ToSingle(HttpContext.Current.Session["Longitude"]);   
                }  
               
                result = DataSetToJSON(dt);  
                return result;  
  
            }  
            catch (Exception)  
            {  
                throw new Exception();  
            }   
        }

<script type="text/javascript">  
        $(function () {  
            var FID = '<%=Session["FID"]%>';  
            var ObID = '<%=Session["ObID"]%>';  
            var No = '<%=Session["No"]%>';  
            var longi = '<%=Session["Longitude"]%>';  
            var latit = '<%=Session["Latitude"]%>';  
            var obj = {};  
            obj.FID = FID;  
            obj.ObID = ObID;  
            obj.No = No;  
            obj.longi = longi;  
            obj.latit = latit;  
            getdata(obj);  
            return falase;  
  
        });  
        function getdata(obj) {  
            $.ajax({  
                type: "POST",  
                url: "home.aspx/mapgriddata",  
                contentType: "application/json;charset=utf-8",  
                data: (data.FFID, data.ObID),  
                datatype: "json",  
                async: true,  
                cache: false,  
                success: function (result) {  
                    window.onload = function () {  
                        alert("map2");  
                        debugger;  
                        var latlng = new google.maps.LatLng(24.0895898, 67.0998546);  
                        debugger;  
                        var mapOptions = {  
                 center: new google.maps.LatLng(markers[0].lat, markers[0].lng),  
                            zoom: 8,  
                            center: latlng,  
                            mapTypeId: google.maps.MapTypeId.ROADMAP  
                        };  
                        debugger;  
                        var infoWindow = new google.maps.InfoWindow();  
                        debugger;  
   var map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);  
                        debugger;  
                        for (i = 0; i < obj.length; i++) {  
                            var data = obj[i]  
                            var myLatlng = new google.maps.LatLng(obj.latlng);  
                            var marker = new google.maps.Marker({  
                                position: myLatlng,  
                                map: map,  
                                 
                            });  
                            debugger;  
                            (function (marker, obj) {  
              google.maps.event.addListener(marker, "click", function (e) {  
                                 infoWindow.setContent(obj.FID,obj.No,obj.latit,obj.longi);  
                                    infoWindow.open(map, obj);  
                                });  
                            })(marker, data);  
                        }  
                    }  
                },  
                error: function (error) {  
                    alert(error);  
                }  
            });  
        } 
  
              
          
        
</script>

protected void Page_Load(object sender, EventArgs e)  
      {    mapgriddata(Convert.ToString(Session["FID"]),Convert.ToString(Session["ObID"]));    
          }  
  
      }