What is the lifetime of local storage?

Answer 1

According to John Resig, it's not possible to specify expiration. It's completely up to the user.

http://ejohn.org/blog/dom-storage/

edit — obviously, your own application can actively remove stuff if it decides it's too old. That is, you can explicitly include some sort of timestamp in what you've got saved, and then use that later to decide whether or not information should be flushed
*** via-Stack Overflow***

Answer 2

very cool!

Answer 3

its on you how you will make the changes
no expiration of any file is determined till you do any changes
you should secure your file every where if it is important