Bind DropDownList using JavaScript using AJAX and DataTable in ASP.Net

I will get requried data from the web method that returns as table!!!

[System.Web.Services.WebMethod]
    public static DataTable call(String code)
    {       
        SqlConnection con = new SqlConnection();
        SqlCommand cmd = new SqlCommand();
        SqlDataAdapter dap = new SqlDataAdapter();

        DataTable tbl = new DataTable();

        con = new SqlConnection(ConfigurationManager.AppSettings["strConn"]);
        con.Open();
        cmd = new SqlCommand("sel_Order", con);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@code", code);
        dap.SelectCommand = cmd;
        dap.Fill(tbl);
        return tbl;
    }