Best User JavaScript and CSS Alternatives in 2026

About User JavaScript and CSS

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 be...