Plugging In Content with a Plug-in

With plug-ins, a browser can display more than just native HTML documents. Plug-ins allow showing full-motion video, audio, 2D and 3D graphics, and a host of other functionalities the browser isn't capable of on its own. For example, with plug-ins, you can watch TV, listen to radio, or hold a videoconference.

A Firefox user can see which plug-ins are installed by entering about:plug-ins in the Firefox location bar. This displays a document listing all the plug-ins currently installed.

Before we install plug-ins, let's discuss the difference between a plug-in and an extension. Aren't they the same? Well, they're not even close to the same:

• Extensions These are additions to Firefox (or Thunderbird) that add a new functionality to the base program. They extend the base program's capabilities.

• Plug-ins These are used to allow a website's content to be displayed in the browser window. Plug-ins deal with the appearance of the page being viewed, but they don't add new functionality to the browser. Plug-ins are third-party applications and include Real's RealPlayer and Adobe's Acrobat Reader. Often a plug-in uses a program to provide the actual capability for example, the Acrobat Reader plug-in uses the Acrobat Reader program.

Caution

A plug-in can affect the browser's security. Use care when installing plug-ins and do a web search to see whether there are any negative side-effects with the plug-in.

Many plug-ins are available for Firefox. Some are common; some are less common. Unlike extensions and themes, most plug-ins come from larger software developers and are not open source. This is not to say that they cannot be open source or user developed, but most are not.

Common plug-ins are supplied by Adobe Systems, Microsoft, Macromedia, Apple, Real Networks, and other larger companies.

Firefox also uses plug-ins to extend the built-in searching capabilities of the browser. Literally hundreds of search plug-ins are available to Firefox users. At last count, I found between 500 and 1,000 search plug-ins (and you thought you were limited to Google, MSN, and Yahoo!).

Other plug-ins are less common, although the actual count varies between platforms (Windows has more than 50, Linux has about 15, and Apple OS/X have about 10).

Most users need only a few plug-ins on their systems. The most popular plug-ins include

• Adobe Acrobat Reader

• Adobe SVG Viewer

• Java Plug-in

• Macromedia Flash Player

• Macromedia Shockwave Player

• QuickTime

• RealPlayer 10

• Windows Media Player

Plug-ins are an important part of Firefox because many of today's web pages use content that requires a plug-in.