A userscript (or user script) is a program, usually written in JavaScript, for modifying web pages[1] to augment browsing. Uses include adding shortcut buttons and keyboard shortcuts, controlling playback speeds, adding features to sites, and enhancing the browsing history.[2]
On desktop browsers such as Firefox, userscripts are enabled by use of a userscript manager browser extension such as Tampermonkey or Greasemonkey. The Presto-based Opera-supported userscripts (referred to as User JavaScript[3]) are placed in a designated directory. Userscripts are often referred to as Greasemonkey scripts, named after the original userscript manager for Firefox.
On Wikipedia, a user scripts feature is enabled for registered users that allows them to install userscripts to augment editing and viewing of the encyclopedia's pages.[4]
script that is run in a Web browser to make live changes to a Web page. These scripts are oftentimes used to add some functionality to a page or to change its appearance. These are typically written in JavaScript, but can be written in other languages as well.
User JavaScript allows you to specify local JavaScript files for Opera to include on every page that you visit.
You can customize Wikipedia in ways that make your editing easier with user scripts, which are written in JavaScript code.