OnClientClick of Button an alert will come which let you know which radio button is checked
HTML:
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
<script type="text/javascript">
function CheckRadio(rd) {
var tr = rd.parentNode.parentNode;
var radiobutton = tr.getElementsByTagName('input');
for (var i = 0; i < radiobutton.length; i++) {
if (radiobutton[i].checked) {
alert(radiobutton[i].nextSibling.textContent);
}
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table border="0" cellpadding="0" cellspacing="0">
<tr>
<th>
ID
</th>
<th>
Name
</th>
<th>
Fav. Color
</th>
<th>
</th>
</tr>
<asp:Repeater ID="Repeater1" runat="server">
<ItemTemplate>
<tr>
<td>
<asp:Label ID="lblId" Text='<%# Eval("ID") %>' runat="server" />
</td>
<td>
<asp:Label ID="lblName" Text='<%# Eval("Name") %>' runat="server" />
</td>
<td>
<asp:RadioButton ID="rbtnBlue" runat="server" Text="Blue" GroupName="UrlColor" Checked="true" />
<asp:RadioButton ID="rbtnRed" runat="server" Text="Red" GroupName="UrlColor" />
</td>
<td>
<asp:Button Text="Find radio" runat="server" OnClientClick="CheckRadio(this)" />
</td>
</tr>
</ItemTemplate>
</asp:Repeater>
</table>
</div>
</form>
</body>
</html>
C#:
protected void Page_Load(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
DataTable dt = new DataTable();
dt.Columns.AddRange(new DataColumn[3] { new DataColumn("Id"), new DataColumn("Name"), new DataColumn("Country") });
dt.Rows.Add(1, "John Hammond", "United States");
dt.Rows.Add(2, "Mudassar Khan", "India");
dt.Rows.Add(3, "Suzanne Mathews", "France");
dt.Rows.Add(4, "Robert Schidner", "Russia");
Repeater1.DataSource = dt;
Repeater1.DataBind();
}
}