Editing Plug-in (computing) (section)

==Mechanism==
[[File:Plug-InExample.svg|325px|thumb|right|Example Plug-In Framework]]

The host application provides services which the plug-in can use, including a way for plug-ins to register themselves with the host application and a [[Protocol (computing)|protocol]] for the exchange of data with plug-ins. Plug-ins depend on the services provided by the host application and do not usually work by themselves. Conversely, the host application operates independently of the plug-ins, making it possible for end-users to add and update plug-ins dynamically without needing to make changes to the host application.<ref name="amo-def">[https://addons.mozilla.org/en-US/firefox/browse/type:7 Mozilla Firefox plugins] – Description of the difference between Mozilla Firefox plugins and extensions under the general term ''add-on''.</ref><ref name="wordpress-def">[http://codex.wordpress.org/Plugin_API Wordpress Plug-in API] – Description of the Wordpress Plug-in architecture.</ref>

Programmers typically implement plug-ins as [[Shared library|shared libraries]], which get [[Dynamic loading|dynamically loaded]] at run time. [[HyperCard]] supported a similar facility, but more commonly included the plug-in code in the HyperCard documents (called ''stacks'') themselves. Thus the HyperCard stack became a self-contained application in its own right, distributable as a single entity that end-users could run without the need for additional installation-steps. Programs may also implement plug-ins by loading a directory of simple [[script (computing)|script]] files written in a [[scripting language]] like [[Python (programming language)|Python]] or [[Lua (programming language)|Lua]].