I am just writing my first ASP .net web app.

I am hoping to avoid a pitfall I have seen in one of the web apps I have to support occasionally.

This app is a series of web based forms.
I often get users calling in saying they have lost 30 mins worth of work because the Internet has timed out on them.

How can I write my application so that it keeps a copy of their data, then allows them to update their data when the connection is working again.

Many Thanks