Customize the way a web page displays or behaves, by using small bits of JavaScript.

Greasemonkey: Customize Web Page Display | Firefox Add-On
Greasemonkey is an advanced Firefox add-on that provides users the opportunity to personalize how a webpage displays or functions. Through scripting small JavaScript snippets, users can modify internet pages, create personalized site scripts, or use existing ones. It also provides a platform for troubleshooting and script hosting.
Add-on stats
Rating: 4.18
1 new ratings
(1,258)
Creation date: 2005-05-20
Weekly download count: 3,615
Firefox on Android: Yes
Risk impact: High risk impact
Risk likelihood:
Manifest version: 2
Permissions:
- <all_urls>
- clipboardWrite
- cookies
- downloads
- notifications
- storage
- tabs
- unlimitedStorage
- webNavigation
- webRequest
Size: 630.49K
URLs: Website
Ranking
# 107 ▼ 3
Other platforms
Not available on Chrome
Not available on Android
Not available on Edge
Want to check extension ranking and stats more quickly for other Firefox add-ons?
Install
Chrome-Stats extension
to view Firefox-Stats data as you browse the Firefox Browser Add-ons.
Add-on summary
Allows you to customize the way a web page displays or behaves, by using small bits of JavaScript.
You can write your own scripts, too. Check out http://wiki.greasespot.net/ to get started. Many scripts already exist, probably ones to enhance your favorite sites. Find them at http://wiki.greasespot.net/User_Script_Hosting .
Having trouble? Please don't post comments here, nobody will see them. If you need help, please read: http://wiki.greasespot.net/Greasemonkey_Manual:Getting_Help
User reviews
Pros
- Easy to use for basic scripting
- Allows customization of web pages
- User-friendly interface
Cons
- Lack of support
- Difficulty finding tutorials
- Some features may not work as expected
Most mentioned
- Need for better support and documentation
- Desire for a dark theme option
- Functionality issues with scripts
User reviews
by Firefox user 18814634, 2025-02-03
.
by y339, 2025-01-30
by Firefox user 18484777, 2025-01-14
Add-on safety
Risk impact
Greasemonkey requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.
Risk impact analysis details
- Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- Critical ****** ****** ** ******* ***** ***** *** ** **** ** ***** **** ******** ****** *** ******** ********** * ******* ********
- High ****** ********* ** * ****** ******** ******** ********** * ******* ******* *****
- High ****** ******* *** ********* ********* ******** ***** *** ** ********** ****** * ******** ******* *****
- Medium ****** ********** ** ******** ********** *** ********* ******* ******** ****** ******** ****** ********
- Medium ******* ******* ************* ***** *** ** ******* *** **** ******* ****** ******** *******
- Low ******* ****** ** *** ********* ********
Risk likelihood
Greasemonkey has earned a fairly good reputation and likely can be trusted.
Risk likelihood analysis details
- Low This extension was updated more than 6 months ago. Older versions are more likely to be stable and safe.
- Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
- Low **** ********* *** **** **** ****** ******* ********** **** ****** ** ** ****** *** *****
- Good **** ********* *** **** **** *******
Upgrade to see full risk analysis details