Web applications commonly use a combination of server-side script (ASP, PHP, etc) and client-side script (HTML, Javascript, etc.) to develop the application. The client-side script deals with the presentation of the information while the server-side script deals with all the hard stuff like storing and retrieving the information.

Most web applications are based on the client-server architecture where the client enters information while the server stores and retrieves information.

Web applications can provide the same functionality and gain the benefit of working across multiple platforms.