$('#addBtn').live("click", function () {


var fullname = $("#nameTxt").val();

var username = $("#usernameTxt").val();

var password = $("#passwordTxt").val();

var address = $("#addTxt").val();

var birthdate = $("#birthdatePickerbox").val();

var contactno = $("#contactTxt").val();


var jsonData = JSON.stringify({ fullname: fullname,
    username: username,
    password: password,
    address: address,
    birthdate: birthdate,
    contactno: contactno
});

$.ajax({

    type: "POST",

    url: "Admin.aspx/addUser",

    data: jsonData,

    contentType: "application/json; charset=utf-8",

    dataType: "json",

    success: function (mydata) {

        $.ajax({

            url: "Admin.aspx/GetAllUsers",
            data: "{}",
            type: "POST",
            dataType: "json",
            contentType: "application/json; charset=utf-8",
            success: function (mydata) {

                clearAddData();

                alert("User successfully added");

                for (var i = 0; i < mydata.d.length; i++) {
                    $("#UserListGrid").append("<tr><td>" + mydata.d[i].userid +
                                              "</td><td>" + mydata.d[i].fullname +
                                              "</td><td>" + mydata.d[i].address +
                                              "</td><td>" + mydata.d[i].birthdate +
                                              "</td><td>" + mydata.d[i].contactno +
                                              "</td><td>" + mydata.d[i].username +
                                              "</td><td>" + mydata.d[i].password +
                                              "</td><td>" + mydata.d[i].usertype + "</td></tr>");
                }
                $("#tbl").append("</table>");

            }
        });

    },
    error: function () {
        clearAddData();

        alert("Failed to Add user");
    }
});
});

<asp:TemplateField Visible="false">
                    <ItemTemplate>
                        <asp:Label ID="MaterialID" Text='<%# Eval("MaterialID") %>' Visible="false" Enabled="false"
                            runat="server" />
                    </ItemTemplate>
                </asp:TemplateField>

((Label)BillOfMaterials.Rows[e.RowIndex].Cells[1].FindControl("MaterialID")).Text