.Net online + Offline

What's up guys! My question is: Has any form or tool been created that allows data to be saved in an offline database if the customer's internet goes down? I will explain better, my application is Web, made in .Net, runs entirely on the Browser and at first, it will record everything in the online database, but what if the client connection drops? I would need this data to be recorded on the client's machine locally, so that when the connection comes back, all this information stored locally would be posted in the online database. Any idea?

Thank you.