c 23 sharp radio button in html how to

1using System;
2using System.Drawing;
3using System.Windows.Forms;
4
5namespace WindowsFormsApplication1
6{
7    public partial class Form1 : Form
8    {
9        public Form1()
10        {
11            InitializeComponent();
12        }
13
14        private void Form1_Load(object sender, EventArgs e)
15        {
16            radioButton1.Checked = true;
17        }
18
19        private void button1_Click(object sender, EventArgs e)
20        {
21            if (radioButton1.Checked == true)
22            {
23                MessageBox.Show ("You are selected Red !! ");
24                return;
25            }
26            else if (radioButton2.Checked == true)
27            {
28                MessageBox.Show("You are selected Blue !! ");
29                return;
30            }
31            else
32            {
33                MessageBox.Show("You are selected Green !! ");
34                return;
35            }
36        }
37    }
38}