Google Gears is an open source browser extension that lets developers create web applications that can run off-line.
Google Gears consists of three modules that address the core challenges in making web applications work off-line.
LocalServer
Cache and serve application resources (HTML, JavaScript, images, etc.) locally
Database
Store data locally in a fully-search able relational database
WorkerPool
Make your web applications more responsive by performing resource-intensive operations asynchronously
Applications that are more than just static files have data that is typically stored on the server. For the application to be useful off-line, this data must be accessible locally. The Database module provides a relational database for storing data. On the Architecture page you will find a discussion of strategies for designing the local storage that your application needs.
When an offline application reconnects, you will need to synchronize any changes made in the local database with the server. There are many different approaches to synchronizing data, and there is no single perfect approach. The Architecture page describes some strategies for synching.
More about Google Gears.
