Greasemonkey is a very popular Mozilla Firefox add-on that allows users to install user scripts to make on-the-fly changes to HTML web page content while augmented browsing on the DOMContentLoaded event, which happens immediately after it is loaded in the browser. Greasemonkey scripts are commonly used to permanently add functions to web pages, customize or change web pages rendering or designing, and numerous other purposes.

There are literally thousands of Greasemonkey user scripts available, and with the popularity of Greasemonkey addon in Firefox, Google Chrome has added support for Greasemonkey user scripts. With built-in Greasemonkey user script support in Google Chrome, user can implement the customizations on Firefox by running the same user scripts in Google Chrome. In fact, user script support is built-in into the core of Chrome and Chromium web browser, so no add-on or plug-in is required to be installed.

Here’s how to use Greasemonkey scripts in Google Chrome:

  1. Download and install Google Chrome in Dev Channel from here (Windows operating system). Mac OS X and Linux users can get the download link for Google Chrome Dev Channel from here.
  2. After install Google Chrome of Dev Channel, just drag and drop any *.user.js JavaScript user script file into any Chrome web browser’s window frame in order to install the user script.

    Alternatively, just click on “Install” link on any Greasemonkey script (in .user.js extension), typically hosted on or other developers’ sites, to install the script.

  3. Prior to installing the script, Chrome will prompt the the following installation warning:

    Extensions and themes can harm your computer. Are you sure you want to continue?

    Install Greasemonkey User Scripts in Google Chrome

    Click on “Continue” button to get the user script installed.

  4. On the “Confirm Installation” dialog box, click on the “Install” button to install the Greasemonkey script.

    Install Greasemonkey User Script in Google Chrome as Extension

After installing a user script, here’s how to disable, uninstall or remove a user script or extension in Google Chrome.