Applet

An applet is a software component that runs in the context of another program, for example a web browser. An applet usually performs a very narrow function that has no independent use. Hence, it is an "app"lication "-let".

The term was used in AppleScript in 1993, but predates that by nearly a decade.

The word applet could alternatively be used to describe a small standalone application, such as those typically bundled with operating systems, for example a calculator program or text editor.

Attributes

Applets and routines

An applet is distinguished from "subroutine" by several features:
* First, it executes only on the "client" platform environment of a system, as contrasted from "servlet". As such, an applet provides functionality or performance beyond the default capabilities of its container (the browser).
* Also, in contrast with a subroutine, certain capabilities are restricted by the container.
* An applet is written in a language that is different from the scripting or HTML language which invokes it. The applet is written in a compiled language, while the scripting language of the container is an interpreted language, hence the greater performance or functionality of the applet. Unlike a "subroutine", a complete web component can be implemented as an applet.

Applets and programs

Unlike a program, an applet cannot run independently; an applet features display and graphics and often interacts with the human user. However, they are usually stateless and have restricted security privileges. The applet must run in a container, which is provided by a host program, through a plugin, or a variety of other applications including mobile devices that support the applet programming model.

Examples

Examples of applets are Java applets and Flash movies. Another example is the Windows Media Player applet that is used to display embedded video files in Internet Explorer (and other browsers that support the plugin). Some plugins also allow for displaying various 3D model formats in a web browser, via an applet that allows the view of the model to be rotated and zoomed. Many browser games are applet-based, though some may develop into fully functional applications that require installation.

See also

* Java applet
* Widget engine

References

[http://www.java.sun.com/applets The Applet source]