Identify multiple instances of my custom visual - on same tab or across tabs

Hi,

I have a custom visual that stores some information in local storage. This works fine as long as user has only one instance of my visual. 

On multiple instances of same visual, i am unable to identify which visual is accessing local storage.

Question: Is there any way, i can assign a unique identifier to each instance? or atleast get tab on which my instance is placed.

Appreciate quick response.