What is a Browser Extension?

Have you ever asked yourself: what is a browser extension or what is a browser plug-in? Browser extensions, plug-ins, and add-ons are generally similar; they are software components that add features to an existing computer program. This can be part of a stand-alone app or part of an internet browser.

For example, a browser extension expands a web browser's functionality by installing specific toolbars, adding buttons or links, or providing other useful functions, like pop-up blocking. A browser extension operates just like any other software, except certain browsers, such as Firefox™ or Chrome, place limits on what they do.

What is a Browser Plug-in?

Browser extensions and plug-ins are generally similar: they are software components (sometimes called "add-ons") that add features to an existing computer program. A plug-in functions a little bit differently, allowing websites to embed and render content through the use of software such as Adobe®, Java®, QuickTime®, or Microsoft® Silverlight. These plug-ins allow you to do things in your browser such as view PDF files or watch videos on sites such as Netflix®.

An illustration of browser extensions in a browser window

What do extensions and plug-ins do?

Applications and browsers support extensions, add-ons, and plug-ins for multiple reasons: to allow third-party developers to create specific functions, to easily add new features, and to expand functionality.

Legitimate application extensions and plug-ins include add-ons that can encrypt and decrypt email, emulate video game consoles, process or analyze sound, and provide text editors. Legitimate browser extensions and plug-ins include search toolbars, media players, and text readers.

These extensions and plug-ins can be very useful and, when developed by an authorized company, safe and harmless to download.

What about malicious extensions?

Some extensions, plug-ins, and add-ons are malicious. They can install adware or spyware, or can redirect your browser to a specific site. These extensions are often installed without explicit user consent and frequently have no easily accessible way to uninstall them.

Malicious extensions can be installed if you click on an unknown dialog box or an ad that goes to a questionable site. Most modern operating systems include an automatic verification to prevent you from downloading unwanted software by accident. If this verification question comes up when you're not actively trying to download something, click “No”.

Close up of a computer screen whereby a mouse pointer is closing a suspicious pop-up window

How to disable browser extensions?

Legitimate extensions, plug-ins, and add-ons can be removed using the "Uninstall" function in your operating system.

For computers running Microsoft Windows:

Windows 10

Step 1: Select the gear icon

Select the gear icon, then “Settings.”

Step 2: Select “System”

Select “System,” then “Apps & features.”

Step 3: Click on the program you want to remove

Click on the program you want to remove and an Uninstall button will appear.


Windows 8 and earlier

Step 1: Click “Start” or the Windows icon, then select “Control Panel.”

Click “Start” or the Windows icon, then select “Control Panel.”

Step 2: Select “Uninstall a program”

Select “Uninstall a program,” then select the program you want to remove.

Step 3: Click “Uninstall”

Click “Uninstall,” then answer the prompts.

Malicious extensions, plug-ins, and add-ons require more work to remove. Even if the malicious software is listed in the program list (it rarely is), you cannot trust that using the operating system to uninstall it will remove all portions of the program. The easiest and best way is to run anti-malware software. When the software finds a malicious program, use the anti-malware program to remove the malicious program. Learn more about anti-malware software.

There are also specific malware removal tools. Choose one that is produced by your operating system developer or by a reputable antivirus software company.

Speed up your Browser

For many users, extensions and plug-ins are incredibly useful, or even completely necessary. But there's a downside: extensions and add-ons can gobble up your system's random access memory or RAM, slowing down its performance.

Upgrading your system’s RAM and adding an SSD are easy ways to speed up both your browser and your system. Find your perfect memory and storage upgrade through the use of the Crucial System Scanner and Advisor.

Plug-ins, add-ons, and extensions can expand the capabilities of your browser or applications. Be sure you get all software from a reputable company to avoid malware. There could be other reasons your system is lagging – our guide on how to fix a slow computer may help.

©2018 Micron Technology, Inc. All rights reserved. Information, products, and/or specifications are subject to change without notice. Neither Crucial nor Micron Technology, Inc. is responsible for omissions or errors in typography or photography. Micron, the Micron logo, Crucial, and the Crucial logo are trademarks or registered trademarks of Micron Technology, Inc. Microsoft and Windows are trademarks of Microsoft Corporation in the U.S. and/or other countries. All other trademarks and service marks are the property of their respective owners.


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