Greasemonkey
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 
(1,256)
Creation date: 2005-05-20
Weekly download count: 3,600
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 See more
Size: 630.49K
URLs: Website
Ranking
# 103 ▼ 2
Other platforms
Not available on Chrome
Not available on Android
Not available on Edge
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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
These summaries are automatically generated weekly using AI based on recent user reviews.
Firefox Browser Add-ons does not verify user reviews, so some user reviews may be inaccurate,
spammy, or outdated. Pros
- Nice extensions
- Perfect
- trop bien
Cons
- nothing works
- no support
- no online tutorials match up with the screen
Most mentioned
- nothing works
- no support
User reviews
by Firefox user 18484777, 2025-01-14
by darcy, 2025-01-11
by Firefox user 18450251, 2024-12-27
Add-on safety
Risk impact
Greasemonkey requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.
Risk likelihood
Greasemonkey has earned a fairly good reputation and likely can be trusted.
Upgrade to see risk analysis details