PLUG INS

A SOFTWARE application designed to extend the functionality of a web browser. Plug-ins are launched from within the browser and are capable of playing audio, showing movies, and running animations, among other things.
All plug in models require two entities the plug-in host and the plug-in itself. The host could be an application, operating system, or even other plug-in. plug-ins are written and compiled entirely from the host, typically by another developer. When the host code is executed , it uses whatever mechanism is provided by the plug-in architecture to locate compatible plug-ins and load them, thus adding capabilities to the host that were not previously available.

When the host application is launched , it searches for all plug-ins with the appropriate identifier. For each plug-in found , the host uses the plug-in architecture to obtain the processing description string and a pointer to the processing function..