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The Bottom Line

Greasemonkey is a Firefox extension which allows you to modify the way web pages display by utilizing JavaScript code. Thousands of unique scripts tailored to a large number of sites are available free of charge. New scripts are published daily by a very active developer community. Users are also given the ability to write their own scripts.


  • Greasemonkey allows you to tweak many of the Web's most well-known sites.
  • The possibilities are practically endless with thousands of user scripts available.
  • Even a novice will find installing and managing user scripts to be extremely easy.
  • Disabling individual scripts can be done quickly through the Greasemonkey interface.
  • Comprehensive resources are available to teach you how to write your own user scripts.


  • Script development is not highly regulated so security flaws can become an issue.
  • Having multiple scripts installed for the same web page or site occasionally causes conflicts.


  • Greasemonkey allows you to install user scripts which modify the appearance and behavior of many popular web pages.
  • Thousands of these user scripts can be downloaded and installed from Userscripts.org.
  • Clicking on the Greasemonkey icon, located in Firefox's status bar, will enable or disable all installed user scripts.
  • Greasemonkey can also be enabled or disabled from the Greasemonkey sub-menu, located in Firefox's Tools menu.
  • Selecting the Manage User Scripts option from the menu or the status bar icon allows you to manage your installed scripts.
  • To remove a user script, select its name in the left pane of the Manage User Scripts window and click on Uninstall.
  • When uninstalling a script, you can also remove any preferences associated with it by checking the appropriate option.
  • To disable a script, select it in the left pane of the Manage User Scripts window and uncheck the option labeled Enabled.
  • You can create your own user script by selecting the New User Script option from the Greasemonkey menu.
  • Web pages and entire web sites can be included or excluded from specific user scripts.

Guide Review - Greasemonkey

The ingenuity of the Firefox add-on developer community and its creations has expanded and continues to expland the power of your web browser in countless ways. The Greasemonkey extension adds yet another avenue for taking Firefox to that proverbial next level. By permitting user scripts that contain behavior ranging from modifying Gmail's visual appearance to removing advertisements from MySpace, Greasemonkey helps you customize your online experience further than you ever thought was possible.

The sheer amount of scripts out there is truly amazing, with more being made available every day. For JavaScript enthusiasts, script kiddies, or those of you looking to get into development at this level, there are plenty of resources and tools to help you get started creating your very own scripts that run with Greasemonkey. When running any user-created code, security is always an issue. Because of this I recommend only downloading from Userscripts.org. Also, if you are a beginner, you may want to only install those scripts which have a decent amount of installs already by other users. These details are displayed along with each script on the site.

Beware when installing Greasemonkey for the first time because you may find yourself immersed in many of the cool scripts available to you. This is truly an addictive and very useful tool for your Firefox browser and it is highly lauded by yours truly.

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