private void button1_Click(object sender, EventArgs e)
        {
            int result;

            if (!IsOnlyEnglish(textBox1.Text))
            {
                //한글이 있으면, username값으로 판정
                result = loginserver(4);
            }
            else
            {
                result = loginserver(2);
            }
            if (result == 2)
            {
                //MessageBox.Show("Login Succesful", "login", MessageBoxButtons.OK);
                YoutubeWallpaper.Form_Main f = new YoutubeWallpaper.Form_Main();
                f.Show();
                Close();
            }
            else
            {
                MessageBox.Show("Error Occured", "login", MessageBoxButtons.OK);
                pass_login("인터넷 연결이 끊겼습니다.");
            }
        }
 private void pass_login(string cause)
 {
     MessageBox.Show(cause, "Login", MessageBoxButtons.OK);
     YoutubeWallpaper.Form_Main f = new YoutubeWallpaper.Form_Main();
     f.Show();
     Close();
 }