Navigator 3.0
navigator.plugins[] navigator.plugins.length
navigator.plugins is an array of Plugin objects, each of which represents one plug-in that has been installed along with the browser. There are navigator.plugins.length elements in the array. The Plugin object provides information about the plug-in, including a list of MIME types it supports.
A plug-in is the Netscape name for a software package that can be invoked by Navigator to display specific data types within the browser window.