Alex E. any ideas???

Alex here's the code I'm using:

<script type="text/javascript">
    function QtyChg() {

        var qty, price;
        var parms;

        qty = 0;
        price = 0;
        parms = "";

        qty = $get('<%=qty.ClientID%>').value;
        price = $get('<%=price.ClientID%>').value;

        parms = "";
        parms = '{"qty":"' + qty + '"}';

        $.ajax({ type: "POST", url: "WebForm1.aspx/QtyMsg", data: parms, contentType: "application/json; charset=utf-8", datatype: "json",
            success: function(datatable) {

                var qtyarr = $.parseJSON(datatable.d);
                var grid = igtbl_getGridById("<%=UltraWebGrid1.ClientID%>");

                while (grid.Rows.length > 0) {
                    grid.Rows.getRow(0).deleteRow();
                }

                $.each(qtyarr.QtyTable, function() {
                    var gridrow = igtbl_addNew("<%=UltraWebGrid1.ClientID%>", 0);
          
                   
                    gridrow.getCell(0).setValue(this.QtyMsg);
                    gridrow.getCell(1).setValue(this.QtyLine);
                   
                });

            }
        });
    }
</script>

What am I doing wrong, I tried to setTargetURL and still nothing