These applications are downloaded from the web and require a web browser to run. No application related components are installed on the device and the application's data is server driven.
The main advantage with web-based applications is that they can be accessed from all devices via the platform's browser and therefore are not confined to a single platform only. This greatly reduces the cost and effort for development and maintenance as only a single application can be used on all platforms.
Also in web-based applications, the data and the application is hosted on a server so maintenance can be done remotely on the server.
The disadvantages of the web-based applications include limited or no access to the APIs that can access device's data, storage, camera and other sensors.