Lazy loading with window scrolling

implmented lazy loading when the window is scolled .

here is the code :-

Javascript:

        $(document).ready(function () {

            function lastPostFunc() {

                $('#divPostsLoader').html('<img src="images/bigLoader.gif">');

                //send a query to server side to present new content

                $.ajax({

                    type: "POST",

                    url: "Default3.aspx/GetDataFromServer",

                    data: "{}",

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

                    dataType: "json",

                    success: function (data) {

                       

                        if (data != "") {

                            $("#dd").html(data.d);

                        }

                        $('#divPostsLoader').empty();

                    }

                })

            };

            $(window).scroll(function () {

                if ($(window).scrollTop() == $(document).height() - $(window).height()) {

                    lastPostFunc();

               }

            });

        });

Code behind :

    static public int initialRecord = 2;

    static public int incrementRecord = 2;

    protected void Page_Load(object sender, EventArgs e)

    {

        if (!IsPostBack)

        {

            initialRecord = 2;

            ShowData();

        }

         

    }

  

    [WebMethod]

    public static string GetDataFromServer()

    {

        SqlConnection sqlConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString);

        if (sqlConnection.State == ConnectionState.Closed)

        {

            sqlConnection.Open();

        }

        DataTable dt = new DataTable();

        using (SqlCommand sqlCommand = new SqlCommand("select Top(" + initialRecord + ") * from Image", sqlConnection))

        {

            SqlDataAdapter sqldataAdapter = new SqlDataAdapter(sqlCommand);

            sqldataAdapter.Fill(dt);

        }

        string str = "";

        for (int i = 0; i < dt.Rows.Count; i++)

        {

            str += "<li><img src='image/MidleImages/" + dt.Rows[i]["image"] + "' width='580' height='360' alt='Grass Blades' /></li>";

        }

        initialRecord += 2;

        return str;

       

    }

    public void ShowData()

    {

        SqlConnection sqlConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString);

        if (sqlConnection.State == ConnectionState.Closed)

        {

            sqlConnection.Open();

        }

        DataTable dt = new DataTable();

        using (SqlCommand sqlCommand = new SqlCommand("select Top(" + initialRecord + ") * from Image", sqlConnection))

        {

            SqlDataAdapter sqldataAdapter = new SqlDataAdapter(sqlCommand);

            sqldataAdapter.Fill(dt);

        }

        string str = "";

        for (int i = 0; i < dt.Rows.Count; i++)

        {

            str += "<li><img src='image/MidleImages/" + dt.Rows[i]["image"] + "' width='580' height='360' alt='Grass Blades' /></li>";

        }

        initialRecord += 2;

        dd.InnerHtml = str;

    }

this will work ...........