user script

A user script is programming that modifies the appearance or behavior of an application. A user script for a Web site, for example, can customize the way that content will display in the host browser.

Typically a brief JavaScript code sequence, a user script for a Web site execute s while a Web page downloads, before any other script is run on the page. There are user scripts to perform a wide variety of tasks on Web sites, for example allowing users to annotate content, change colors and formats, debug site code, or remove ads. To install and run Web site user scripts, you must first install a browser extension, such as Greasemonkey , which will intermediate between the browser and Web servers.

Although user scripts can improve the appearance and functionality of Web content, like other software, they can also contain malicious coding ( malware ) and should only be downloaded from trusted sources.