For disabling RadListView
completely at the client side, you need to disable the active links/images/inputs/spans/etc which is inside the listview manually. So you have to add codes additional to
"document.getElementById('<%=Listview.ClientID %>').disabled = true"
in order to achieve that. Please check the below link for more information, which will help you to disable RadListView
from client side. The link contains information about the RadGrid, however disabling the RadListView on client side is the same.
the Telerik team