NPAPI plugin developer guide

This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Plugins are shared libraries that users can install to display content that the application itself can't display natively. For example, the Adobe Flash plug-in is used to access Flash content (including videos and certain interactive applications), and the QuickTime and RealPlayer plugins are used to play special format videos in a web page.

Important: Plugins are now a legacy technology. They are not available on most mobile devices. Mozilla encourages website developers to avoid using plugins wherever possible. If there are plugin features which are not available in the web platform, we encourage developers to post their use cases to project list, so that Mozilla can prioritize web platform work to make those use cases possible.

Plugins are written using NPAPI, the cross-browser API for plugins. The main source of documentation for NPAPI is the NPAPI plugin API reference. To make your plugin scriptable from web pages, use npruntime.

Plug-in Basics

Plug-in Development Overview

Initialization and Destruction

Drawing and Event Handling




Version, UI, and Status Information