populating a dropdown from database using javascript webservice

Paste the webmethod code here. Use Code or Add Code button in editor to add code

 [WebMethod(EnableSession = true)]

        public DataSet Findsome(string s)
        {
            string constr = "Initial Catalog=.........................";
            conn = new SqlConnection();
            conn.ConnectionString = constr;//Session["Constr"].ToString();
            conn.Open();

            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "Select distinct " + s + " from table  ";
            //cmd.Parameters.AddWithValue("@some", s);
            cmd.Connection = conn;
            SqlDataAdapter da = new SqlDataAdapter(cmd);

            DataSet ds = new DataSet();
            
            da.Fill(ds, "table");
            return ds;

        }

but this code is in a sepereate .asmx page

Place it in the same page as the sample allows you to call methods on same page

If you want to call Web service you will need to set Service Url parameter in ScriptManager

ok

now i am trying in the same page ie .aspx.cs

with reference to u r code

but i get error

    [System.Web.Services.WebMethod]
    public static List<Country> GetCountries()
    {
         string constr = "........";
         conn = new SqlConnection();
                conn.ConnectionString = constr;// 
                conn.Open();
        string sql = "Select distinct city from table";
        SqlDataAdapter da = new SqlDataAdapter(sql, conn);
        DataTable dt = new DataTable();
        da.Fill(dt);
        string[] items = new string[] {
                (dt.Rows.Count - 1)};
        int i = 0;
        foreach (DataRow dr in dt.Rows)
        {
            items.SetValue(dr["city"].ToString(), i);
            i++;
        }
        return items;
    }



    public class Country
    {
        private string _name;
        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }

        private string _id;
        public string Id
        {
            get { return _id; }
            set { _id = value; }
        }
    }

Can you let me know the error that you get