User Script Manager
A user script manager is a browser extension or standalone tool that allows users to install, manage, and run custom JavaScript scripts (user scripts) on web pages to modify their appearance, behavior, or functionality. It provides a centralized interface for enabling/disabling scripts, updating them, and handling permissions, enhancing web browsing by automating tasks or adding features. Popular examples include Tampermonkey, Greasemonkey, and Violentmonkey, which work across various browsers like Chrome, Firefox, and Edge.
Developers should learn and use user script managers to automate repetitive web tasks, customize websites for testing or personal use, and prototype browser extensions quickly without full deployment. They are particularly useful for web scraping, debugging, adding missing features to sites, or creating lightweight tools for specific workflows, as they allow rapid development and testing of scripts in real browsing environments.