Description from extension meta
User JavaScript and CSS on any website
Image from store
Description from store
Userscript's and userstyle's — simple extension to inject own JavaScript or CSS rules to any page.
Features:
- Instant execution
- Custom libs include
- URL masking allows use one script or CSS on many pages
Documentation:
https://tenrabbits.github.io/user-js-css-docs/
Change log:
Version 3.1.0
- Starting from Chrome version 138, the method for allowing user scripts in the browser has changed
- Fixed a bug where styles weren't removed when a rule was deleted
- Fixed a bug where not all rules applied to the page were shown in the rules popup
Version 3.0.6 beta
- `try catch` wrapper removed
- CSS injection improved
- added button to save converted URL
Version 3.0.5 beta
- the mode of injection of styles into the DOM has been returned
- minor fixes
Version 3.0.3 beta
- modules are now in the same scope
- CSS injection improvement
- and other minor fixes
Version 3.0.2 beta
- hotfix: fixed bug with registration and deletion of scripts
- added feature to change start scripts before page loading
- added feature to strictly read URL patterns
Version 3.0.1 beta
- Improved CSS injection
- Fix loading external modules when replacing storage
Version 3.0.0 beta
- The extension has been moved to MV3
- Added option to inject scripts and styles in iframe
- Added the feature of live CSS
- Added the One Dark theme and a few other improvements
Version 2.0.0
- 90% of the code has been rewritten;
- Improved UI;
- Added SASS support;
- Added Prettier formatter
- Other minor improvements
Version 2.0.0
- 90% of the code has been rewritten;
- Improved UI;
- Added SASS support;
- Added Prettier formatter
- Other minor improvements
Version 1.2.8
- Added function for naming rules
- Updated translations
Version 1.2.7
- Updated all extension libraries to current versions
Version 1.2.6
- Fixed error in console "Unchecked runtime.lastError: The message port closed before a response was received"
- Improved domain getter from URL
- Updated Ace Editor and jQuery to latest
Version 1.2.5
- Resolved bug with '@import' and "Auto-important css" feature
- "Auto-important css" feature now disabled by default
- Added feature to exclude URL's by '!' symbol at start
- Updated jQuery and Ace editor to last versions
- Other small fixes
Version 1.2.4
- Added manual cloud sync in testing mode
- Improved "auto-important css" feature
- Other small fixes
Version 1.2.1
- Fixed algorithm of "high priority CSS"
Version 1.2.0
- Added toggle button in site list
- Added documentation tab
- Added 'Vintage mode' option to Ace Editor
- Updated jQuery, Ace Editor to last versions
- Other small fixies
Version 1.1.5
- Returned old method injection and added option to toggle this. Alternative method has feature to avoid CORS issues, but has only DOM access to site (no JS context). Old and now primary method is injecting by <script> tag on site bottom.
- Added scroll past end in editor
Version 1.1.2
- Minor bug fixes
Version 1.1.0
- Added new injection system that increased perfomance
- Added feature: few URLs in one rule (separate by commas)
- Added word wrap setting
- Added CSS auto !important option
- Minor changes
Version 1.0.2
- Hot fixes
Version 1.0.0
- Full redesign of extension
- Added more settings
- Added toggleable counter on extension icon
Version 0.98
- Fix bug that prevent create new rules
- Minor changes
Version 0.96
- Full redesign of extension interface
- 80% code of extension core has been rewritten
- New feature: change URL field and mask with "*" symbol (eg *.expample.com)
- Editor window opens in new tab in split layout
- Disabled autosave feature
- Configurable editor in settings
- New icon
Version 0.94
- Hotfix editor opening bug
Version 0.93
- Fixed a bug where JavaScript is not always inserted in a page
- Outdated processes are disabled
Version 0.92
- Code autosave work on all pages
Version 0.91
- Fix ".co.uk" zone parse
- Other small fixes
Version 0.90
- Improve core
- Add feature to load own libraries
Beta test. If you find any problem or have a question contact me on email.
Latest reviews
- (2025-07-09) Dongwon Lee: On Chrome 136, enabling Developer Mode in the extensions manager allows the ‘User JavaScript and CSS’ extension to apply CSS as expected, but JavaScript fails to run.
- (2025-07-03) Swanson Samsonite: Great app, but newest chrome version just broke this because of changes google made. Looking forward to updates!
- (2025-06-19) Dmitry Zhylski: Really useful and cool extension!
- (2025-06-10) SANKALP RAUL: Awesome, it works great! Thank you <3
- (2025-06-10) Karolina Poremba: Why do I have to reload the page every time I visit it for the CSS to load?
- (2025-05-27) Lars E.rnst: Beautiful, free, powerful, SASS support, the best of it's kind!
- (2025-05-26) Henrik Bendorf: I just love it! Thanks for the awesome extension in terms of UX and functionality!
- (2025-05-21) Dharma Jannyter: Awesome extension! Love the combo of JS and CSS/SCSS both in one + the nice dark themes. 👌 Just one question out of curiosity: Is there any performance impact (positive or negative) when enabling the "Isolated Environment", maybe due to some overhead or similar?
- (2025-05-20) Benjamin Moran: You can create multiple JS and CSS scripts for each website and name them, toggling them on/off as needed. Text editor is color-coded and easy to work with. Super useful for anyone who knows a little code and wants to customize their browsing experience.
- (2025-05-05) Dan Rotaru: Great extension, thank you, but there is a moment that can be improved. Please, add possibility to load js/css from files, to work inside your favorite IDE and after saving it to load them in extension.
- (2025-05-01) Jac Chambers: Genuinely phenomenal. Worked just like I wanted it to, right out of the box. Great stuff.
- (2025-04-22) Steve Mitchell: Used for CSS. Works perfectly. Thanks!
- (2025-04-14) Tomer Cohen: this extension does what it says on the can. it just works. great. maybe missing a way to share scripts/css, but i get it, security and all.
- (2025-03-27) Jay White: Absolutely the best extension I've been looking for. Finally I can hide all those useless things I never want to see. Thank you for this perfect extension
- (2025-03-24) Dhruv Erry: Perfect. The auto !important is a very useful button.
- (2025-03-17) Shelby: Splendid extension. I use it to test js injection for work to digest and convert tables into interactable ChartJS canvas elements, or for personal handy things like spitting out drive distances on an auctions site so I can easily see how far each one is- and it is absolutely perfect.
- (2025-03-11) Ben: Its a great extension for online sites. However as a developer, the extension seems to be causing AntiForgery token errors on localhost with the error '__RequestVerificationToken' is not present. This even happens if I don't have a rule on my localhost site. The moment I disable the extension, it all works again.
- (2025-03-08) Endre Varga: Works! Működik! 🙏
- (2025-03-05) Ian Cadle: Brilliant extension :)
- (2025-02-25) 田中龍一: I would like to migrate my JS & CSS settings from Chrome to Vivaldi. Do I have to copy and paste them one by one?
- (2025-02-17) Isaac B: Great extension. Only thing that's missing is the option for a vertical split between the editors for vertical monitor setups. Would be perfect with that added.
- (2025-02-06) Dan Rotaru: Great extension but not too much customization. Suggestion for developer: - add possibility to share your piece of code with others (ability to install my code for other users); - add possibility to create custom snippets in editor (for now autocomplete works not as well as I want), so this feature will fix it; - add One Dark Theme, idk why this theme is not added, is the most popular theme in VS Code, Jetbrains editors... - can't choose editor font family But in general it's ok, good job!
- (2025-02-04) todokuro: Very good and more stable than Tamperamonkey/Violentmonkey. It also works with Edge canary on Android, but unfortunately the icons such as “run on startup” are hidden in the browser bar.
- (2025-01-27) Nathan Lenkowski: Does one thing and does it right. This is the code injection extension you're looking for.
- (2025-01-14) NOCauseEffect: Amazing Extension
- (2025-01-11) Anastasios Sar.: Very good extension, respect!
- (2024-12-23) Gavo 1002: weird how when i save it jumbles up all my code :(
- (2024-12-05) Michael Orr: Superb. Works really well, and a great UI.
- (2024-12-02) Waqas Asghar: Look very good with nice clean interface!
- (2024-11-27) Maxime: Great extension, I love that I can find the same features and shortcuts as in VS Code, it's really a great experience ^^
- (2024-11-27) John Hines: Holy Cow...this is a good one
- (2024-11-06) Jared Meadows: I love that it allows a quick toggle, so I'm not forced to have a specific rule on all the time, but I can turn it on, only when I need it! ❤️
- (2024-11-05) Ilm markazi asosiy: Super!!!
- (2024-10-28) Mohamed Hassn: I love it very much but I have a problem it works on chrome perfectly and also on android Kiwi Browser and but now it doesn't work on android Kiwi Browser I hope you to solve this problem please
- (2024-10-27) Jeremy Shepherd: nice
- (2024-10-21) ayii: "Could you add a feature that allows switching between JS or CSS editing panels via a tab? Also, the left sidebar is too large, making the entire code editing area feel cramped and somewhat overwhelming."
- (2024-10-13) FrontEnd Neo: Perfectly worked for my requirements. Thanks. Much appreciated.
- (2024-10-10) Nitigya Joshi: Works most of the time but sometimes it caches the old code and even after multiple changes, they don't get reflected on the site.
- (2024-10-06) Andreas Sefzig: This is one of my most frequently used tools. Love the purpose, usability and the constant, seamless improvement. Kudos to the developer: you are part of my internet, my work and my workflows, <3.
- (2024-09-28) Pritam Koloursyncc: Very useful
- (2024-09-14) Greg Perham: Just started using it. Very nice. One thing that would make it more perfect is if the CSS updated in open tabs upon save. The Programmatic Injection implies that it will load edits without reloading open tabs, but my experience is that the styles either do not get injected at all, or still require the tab to be refreshed.
- (2024-09-09) Zoran Medojevic: Great tool - allowed me to customoze and improve some manual work on website that is not mine :)
- (2024-09-03) Sreeraj S: Excellent app. Do the job perfectly. Thank you very much - posted in Jul 8, 2019 Updates: In 2024, it is not working properly; sometimes it works, but I don't know why. The previous version was excellent. I am using Google Chrome
- (2024-09-03) Sreeraj S: Excellent app. Do the job perfectly. Thank you very much - posted in Jul 8, 2019 Updates: In 2024, it is not working properly; sometimes it works, but I don't know why. The previous version was excellent. I am using Google Chrome
- (2024-09-02) Максим Покровский: Incredibly well-executed product with a sleek design, well-written code, and an intuitive UI. It has solid documentation and not-commerciall yet. I hope it would be open-sourced on GitHub to build more trust, ensuring it doesn’t follow the unfortunate path that Stylish did. Anyway If you're looking for an extension that allows you to tweak your favorite websites, look no further.
- (2024-09-02) Enzo Vang: how do i use it
- (2024-08-27) Todd Freeman: I needed a replacement for CJS, which Chrome was warning me would be going away. I could not be more delighted to have been forced to find a replacement. I love the editor, which is beautiful and has a nice dark, default skin. And I was very happy to see support for CSS **and** SCSS! I haven't tried style injection yet, but I like the idea of having one extension to do custom scripts and styling. The only thing I can think of that it may be lacking is limited module support. For my needs, jQuery is just fine, but I believe CJS may have had more libraries you could load along with your scripts.
- (2024-08-26) Mikhail Oleynik: So helpful!
- (2024-08-24) Steven Sypien: Good.
- (2024-08-23) Damian S: What can I say... it works brilliantly! 10/10! Currently using it to password protect certain sites like web.whatsapp, photos.google.com, so that if a co-worker happens to be using my PC, they can't view my stuff.