As Tichy mentioned, there are the offline web apps, basically the application works offline and only uses the internet connection if it is available. It is even

As Tichy mentioned, there are the offline web apps, basically the application works offline and only uses the internet connection if it is available. It is even possible to have an application almost indistinguishable from a desktop application depending on the browser (Chrome, iPhone/iPod, etc) The advantages of using this platform is that it is cross-platform, the application will have a really long longevity and "everyone" knows javascript (which might be a good or bad thing).