The approach I typically take is to send down the naming container (namespace) for its parent into a client-side variable. Something like,
ClientAPI.RegisterClientVariable(Me.Page, "tabstripNS", MyDNNTabStrip.NamingContainer.ClientID, True)
Then on the client
dnn.controls.controls[dnn.getVar('tabstripNS') + '_' + 'MyDNNTabStrip');
Or simply register the tabstrips clientID if you only need to reference that.