```
<asp:RadioButton ID="myButton" Text="Option" GroupName="group" runat="server" />

```

Why in this case javascript function call `$find('<%= myButton.ClientID %>')` return `null`? I need to detect/change value in client javascript. `$find()` should be shortcut for `Sys.Application.findComponent()`.

UPDATE: There is no problem with ID, i tried $find() in chrome console with real rendered id and still getting null. And i want to get Ajax control, not DOM element.