Get RadioButtonList selected value by jQuery/JavaScript

How to get radio button list selected value from a list of radio buttons by using either jQuery or JavaScript

<asp:RadioButtonList ID="rbtnCardType" runat="server">  
   <asp:ListItem Value="1" Text="Visa" />
   <asp:ListItem Value="2" Text="Master" />      
   <asp:ListItem Value="3" Text="Maestro" />  
</asp:RadioButtonList>   

use on click even on radio button list and get all input types and try to get selected value by using for loop

<asp:RadioButtonList ID="rbtnCardType" runat="server" onclick="CardChanged(this)">  
   <asp:ListItem Value="1" Text="Visa" />
   <asp:ListItem Value="2" Text="Master" />      
   <asp:ListItem Value="3" Text="Maestro" />  
</asp:RadioButtonList>  

function CardChanged(rbtn){    
 var radios = rbtn.getElementsByTagName("input");
 for (var i = 0; i < radios.length; i++) 
      if (radios[i].checked) 
         return radios[i].value;
}

you can also use this

$('#<%=rbtnCardType.ClientID %> input[type=radio]:checked').val();