Userscripts are small JavaScript programs that can be run in a browser to customize a website. They are a type of augmented browsing technology, allowing users to add their own personal improvements to the sites they visit. For example, a user could add movie review information (from Metacritic, Rotten Tomatoes, etc) to the information displayed by their streaming services. Sites like greasyfork.org and openuserjs.org contain large catalogs of customizations that users have built. Tampermonkey is a userscript manager that can find and install userscripts, execute them, and keep them up to date. On Tampermonkey's dashboard, users can see which userscripts they've installed, which sites they apply to, and what permissions each script requires. Libraries of scripts can be exported to Google Drive, Dropbox, or OneDrive and shared with other users. Tampermonkey is available for Google Chrome, Mozilla Firefox, Microsoft Edge, Safari, and Opera as well as a number of other browsers.