I do not think that the Local Storage API allows you to determine the physical location of the stored data. It just allows you to store key / value pairs in a user's browser through JavaScript, such as a cookie, except that it remains local and not transmitted to the server.
The browser may want to put its local storage data on the SD card or on the device on which it works, but you cannot check the physical location of the data.
. http://diveintohtml5.ep.io/storage.html#localstorage .