Programming - Netscape Gecko Browser Plugins

The NPAPI (or Netscape Plugin Application Programming Interface) is the cross-platform plugin architecture used by many web browsers. It was first developed for the Netscape family of browsers starting with Netscape Navigator 2.0 but has subsequently been implemented in other browsers including Mozilla Application Suite, Mozilla Firefox, Safari, Opera, Konqueror and some versions of Microsoft Internet Explorer.

Its success can be partly attributed to its simplicity. A plugin declares that it handles certain content types (e.g. "audio/mp3") through exposed file information. When the browser encounters such content type it loads the associated plugin, sets aside the space within the browser content for the plugin to render itself and then streams data to it. The plugin is then responsible for rendering the data as it sees fit, be it visual, audio or otherwise. So a plugin runs in-place within the page, as opposed to older browsers that had to launch an external application to handle unknown content types.

We have developed a simple Netscape Plugin which can be loaded into FireFox, safari and Opera. Sample code is provided with this article.