asp:RadioButton javascript onclick event

 aspx page

<script language="javascript" type="text/javascript">
  
    function clicking(Obj)
    {
       var a=document.getElementById("ctl00_ContentPlaceHolder1_ctl20_AAA1_rbtnStudent");
       var b=document.getElementById("ctl00_ContentPlaceHolder1_ctl20_AAA1_rbtnAllStudents");
       switch (Obj.value)
       {case "rbtnStudent":
            a.checked=true;
            b.checked=false;
            break;
        case "rbtnAllStudents":
            b.checked=true;
            a.checked=false;
            break;
        default:break;
       }
         
   }
</script>

<asp:RadioButton ID="rbtnStudent" runat="server" Checked="true"   Text="Student"  /> <br />
<asp:RadioButton ID="rbtnAllStudents" runat="server" Text="All Students" />

vb.net Page_Load

rbtnStudent.Attributes.Add("onclick", "clicking(this)")
rbtnAllStudents.Attributes.Add("onclick", "clicking(this)")