how to make radio button work without postback

my Div2 contains a datalist with a radio button,,when i click on radio button it gets the filename of the corresponding image with it,,currently this is happening with postback,,i want to select the options without postback...

protected void rdb4_click(object sender, EventArgs e)
{
            string value = "";
            for (int i = 0; i < DataList4.Items.Count; i++)
            {
                RadioButton rdb4;
                rdb4 = (RadioButton)DataList4.Items[i].FindControl("rdb4");
                if (rdb4 != null)
                {
                    if (rdb4.Checked)
                    {
                        HiddenField hf = (HiddenField)Dat开发者_高级运维aList4.Items[i].FindControl("HiddenField4");
                        value = hf.Value.ToString();
                    }
                }
            }
}

how to make radio button work without postback

Use AJAX.

Ajax Page

And this for partial page update toturial:

Partial Page Update