| Name | Form | Features | Compatibility | Last Updated |
|---|---|---|---|---|
| bookmarklets | JavaScript | Can execute arbitrary JavaScript on any page, but requires a user to click them, rather than running automatically | Always working | |
| Firebug | Firefox extension for developers | Allows arbitrary real time changes to a page's DOM | 2017 | |
| Greasekit | Provides userscripting for Safari (WebKit) | 2008 | ||
| Greasemonkey | Browser extension | Alters the output of web content immediately after being displayed | Firefox, Chromium browser and Opera. | 2021 |
| Tampermonkey | Browser extension | Userscripts manager that provides features like a clear overview over the running scripts, a built-in editor, ZIP-based import and export, automatic update checks, and browser- and cloud storage-based synchronization | Firefox, Chromium browser and Opera. | 2022 |
| iMacros | Firefox, Chromium browser, and Internet Explorer extension | Allows the user to record and replay "Internet Macros" for web automation, web scraping, or web testing. | 2018 | |
| Proxomitron | Proxy-level language | Available since late 1990s, predates JavaScript active browsing and provides a similar function for all browsers using a regular expression-like matching language | 2003 | |
| Stylish | Firefox extension using Cascading Style Sheets | Client-side manipulation of webpage content | 2022 | |
| Violentmonkey | Browser extension | open source alternative to Greasemonkey | 2024 |