Mozilla Firefox offers several ways in which other programs can change it's behavior and improve it's features. For example, Mozilla Firefox can not, by itself, display highly animated web sites. But, because Mozilla Firefox can be extended, another company called Macromedia has created an extension plug-in called Flash, which can display multimedia web sites. Many other enhancements, like download managers, etc, are also available.
The extension plug-ins are software programs that extend the capabilities of the browser in a specific way - giving you, for example, the ability to play audio samples or view video movies from within your browser.
There are also some examples that are not so nice: spyware and adware makers have developed Mozilla Firefox BHOs which help them track the pages you visit and your purchase habits on the web. Many times, these extensions are badly written and crash or slow down Mozilla Firefox.
The Mozilla Firefox Extensions tool allows you to disable or uninstall any extension.
In the upper list, you can see all the Mozilla Firefox extensions that are installed on your computer.
The Disable button disables an extension and moves it to the bottom list. Disabling an extension means that it won't be loaded or used by Mozilla Firefox, so it won't have any influence on your computer.
The Remove button directly removes and erases an extension.
You can, at any time, enable an extension by pressing the Enable button.
If you use the Mozilla Firefox Extensions tool to disable some spyware/adware, we recommend you to also use the Startup Manager tool and carefully examine your startup programs. Some spyware extensions might come together with programs that run at startup.