Up to know there was a scenario to store the client side input value which require for further process was being stored in session parameter value or query string value.

But with HTML5 App database, now you can store client side parameter in temporary database and can use with other application for small amount of time. it can be stored in certain time if somehow client got dis connected with server. So it will open new way of client side validation and usage of that data for different functionality and application.