radio button on change not working

 Hi all,
 i m  using access keys to navigate Radio buttons. but when i use Onchange on access keys it doesn't work??
 This is the Radio Button

                               <asp:RadioButtonList ID="rbtn" runat="server" Width="220px"   onchange="GetRadioChange();" >
                                            Style="text-align: left" >
                                       &nb ...