but wouldn't it be nice if Firefox could play movie clips and songs without forcing you to divide your attention among multiple programs? You're in luck. Firefox isn't designed to be a multimedia masterpiece in and of itself (that's what Web pages are responsible for), but it can emulate the experience through the use of browser plug-ins. Plug-ins are an advanced technology that most people should never have to worry about, but the basic idea is that you can literally insert programs into Firefox to give it newfound capabilities. Firefox can't play movies? No problem. Apple's QuickTime program can, so Firefox embeds QuickTime into the Content area. Now you've got the power of a full-fledged movie player with the convenience of in-browser playback. Your computer probably already contains most of the plug-ins you'll need, such as Adobe Acrobat for electronic documents, but I describe how to obtain missing plug-ins in the following section. Finding plug-ins you might need As you explore the Web, you might encounter content that requires plug-ins you don't already have, such as Flash for complex, animated Web sites. In such cases, Firefox displays a toolbar above the page to notify you that a plug-in is required. You also see an empty box on the page with a green puzzle piece inside, as shown in Figure 11-4. Figure 11-4: Hmm. Something must be missing here. Click the puzzle piece to retrieve the missing plug-in. This box is where the plug-in content would load if the plug-in were available, and the puzzle piece represents the missing plug-in. Click the puzzle piece to have Firefox find the plug-in and walk you through the installation process as follows: 1. Click the green puzzle piece to open the plug-in installation wizard, shown in Figure 11-5. Figure 11-5: The plug-in installation wizard walks you through the process of installing a missing plug-in when you encounter a site that needs it. Firefox searches for available plug-ins. Any matches it finds are displayed in a list and installed by default. If multiple plug-ins are available, you can indicate which plug-ins you don't want to install by deselecting the check boxes next to their names. 2. Click Next to continue. 3. Read through the license agreement for the plug-in you're installing. This agreement outlines the terms and conditions under which you can use the plug-in, and explains the rules governing the plug-in's behavior. 4. Select I Agree and click Next to continue with installation. Firefox downloads and automatically installs the plug-in. This process should take less than a minute, at which point the completion screen appears. 5. Click Finish to close the wizard. Some plug-ins require you to restart Firefox before they work. Otherwise, Firefox automatically loads the content that required the plug-in in place of the empty box with the puzzle piece as soon as installation finishes. Tip Although Firefox maintains a comprehensive plug-in database (located at https://pfs.mozilla.org/plugins), you might encounter a Web site that requires a rare plug-in that Firefox can't find. In that case, you need to find the plug-in yourself on the Internet or you will be unable to view the content that requires it. Overriding default actions with Save Link Sometimes, Firefox might act on your behalf in undesirable ways due to the automatic settings I discuss in "Bypassing the download decision window," earlier in this chapter. Perhaps you click a link with the intent to save the file to which it links, but Firefox opens the file automatically. Or perhaps