How can I determine the SelectedValue of a RadioButtonList in JavaScript?

Question

I have an ASP.NET web page with a databound RadioButtonList. I do not know how many radio buttons will be rendered at design time. I need to determine the SelectedValue on

Answer 1

From here:

if (RadioButtonList1.SelectedIndex > -1) 
{
    Label1.Text = "You selected: " + RadioButtonList1.SelectedItem.Text;
}