Grease Monkey

Interactive Media Device

By Jessica Brown

What is it?

• Grease monkey is an extension of Mozilla Firefox that allows users to install scripts when they are needed to most HTML Web pages.

• Examples:

• Fixing or rendering bugs

• Combining data from multiple Web pages

Details

• Grease monkey user scripts are written by hand using a JavaScript code which manipulates contents of Web page using the Document Object Model Interface.

• Userscript.org maintains a database of Grease monkey scripts, and for each one it lists the URLs of web pages to which the scripts pertain.

More Details

• Writing a Grease monkey script is similar to writing JavaScript for a web page, with some additional restrictions imposed by the security provisions of Mozilla's XPCNativeWrappers.

• In addition to JavaScript code, Grease monkey scripts contain limited optional metadata, which specifies the name of the script, a description, a namespace URL used to differentiate identically named scripts, and URL patterns for which the script is intended to be invoked or not.

Typical Grease Monkey Scripts

• Auto fill forms.

• Alter the formatting of text, borders, graphics, etc.

• Remove specific content, such as advertising, pop-ups, even whole sections of a page.

• Alter content and layout beyond what the page author considered.

More Scripts

• Add links, buttons, or any other type of HTML element anywhere on the page.

• Enhance the content of pages by correlating information from related pages on the same site, or other sites.

• Add extended JavaScript behavior to pages.

Problems

• Possible disruption to revenue of some Websites.

• Increases in the Web traffic that arise from some scripts.

• The proliferation of scripts acting on many pages and the difficulty of distinguishing whether problems in a page are caused by actual Web-programming bugs or by local Grease monkey scripts, may make troubleshooting defects more difficult.

More Problems

• Script errors resulting from lack of coordination between Grease monkey developers and the original Website developers.

• Grease monkey only works on HTML-based pages, and does not work on Java, Flash, Flex, and Silver light content within Web pages.

• Rich Internet Applications are more difficult for a Grease monkey script developer to control than static Web pages.

• The original site developers can release a new version of the site that causes the Grease monkey script designed for that site to stop working.

• There is no official way for user scripts to update themselves; some developers added such functionality to their user scripts but most of them remain static and eventually break.