Who should use User JavaScript and CSS?

User JavaScript and CSS is a consumer product built for firefox users and web developers.

Is User JavaScript and CSS free?

Yes — User JavaScript and CSS is free to use.

What platforms does User JavaScript and CSS run on?

User JavaScript and CSS runs on the web and embeddable surfaces.

Is User JavaScript and CSS still active?

Unverified. User JavaScript and CSS has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.

What projects are similar to User JavaScript and CSS?

Similar projects tracked by PulseGate include Custom Site JS, Custom CSS, and Your Custom Css.

Who develops User JavaScript and CSS?

User JavaScript and CSS is developed by tenRabbits.

How long has User JavaScript and CSS been around?

User JavaScript and CSS first shipped in 2026.

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User JavaScript and CSS

Name: User JavaScript and CSS
Author: tenRabbits

mozilla.orgBrowser DevTools & extensions

User JavaScript and CSS is a Firefox extension for applying custom JavaScript and CSS to websites. It supports URL matching, instant script and style injection, and custom libraries for users and web developers.

FreeWebEmbeddable

Visit mozilla.org

Overview

5 features

In the Browser DevTools & extensions space, User JavaScript and CSS takes a focused approach. It focuses on applying custom JavaScript and CSS to websites without modifying their source code. It is built as a consumer product for firefox users and web developers. User JavaScript and CSS costs nothing to use. It ships for the web and embeddable surfaces.

tenRabbits builds and maintains User JavaScript and CSS, and it first shipped in 2026. Key capabilities include Custom JavaScript, Custom CSS, and URL matching. The interface is available in 32 languages, including Czech, German, and Greek.

Summary written by a language model from the project’s public pages.

Custom JavaScript
Custom CSS
URL matching
Custom libraries
Instant injection

Built with & integrations

Runs on

BrowserEmbeddable

Trust & compliance

Verified signals

HTTPSPrivacy Policy Terms of ServiceFree tierMulti-languageStore-verified publisher

Legal

Indexing history

What PulseGate has recorded for this listing

Indexed12 Sep · 09:30 UTC
User JavaScript and CSS verified via Firefox Add-ons
Source: Firefox Add-ons · Open

Frequently asked questions about User JavaScript and CSS

What does User JavaScript and CSS do?: User JavaScript and CSS focuses on applying custom JavaScript and CSS to websites without modifying their source code. It is catalogued under Browser DevTools & extensions on PulseGate.
Who should use User JavaScript and CSS?: User JavaScript and CSS is a consumer product built for firefox users and web developers.
Is User JavaScript and CSS free?: Yes — User JavaScript and CSS is free to use.
What platforms does User JavaScript and CSS run on?: User JavaScript and CSS runs on the web and embeddable surfaces.
Is User JavaScript and CSS still active?: Unverified. User JavaScript and CSS has not been re-checked since it entered the index, so there is no finding either way — and only a positive finding would say otherwise.
What projects are similar to User JavaScript and CSS?: Similar projects tracked by PulseGate include Custom Site JS, Custom CSS, and Your Custom Css.Custom Site JS Custom CSS Your Custom Css
Who develops User JavaScript and CSS?: User JavaScript and CSS is developed by tenRabbits.
How long has User JavaScript and CSS been around?: User JavaScript and CSS first shipped in 2026.

At a glance

Pricing: Free
Platforms: Web
First seen: 12 Sep 2026
Built for: Firefox users and web developers
Model: B2C
Solves: Applying custom JavaScript and CSS to websites without modifying their source code.

Registered as

Firefox Add-ons: user-js-and-css

Developer

tenRabbits

Index record

Indexed: 12 Sep 2026
Lifecycle: Alive
First seen: Sep 2026
Last seen: 12 Sep 2026

Identity audit (13)

Slug: user-javascript-and-css-mozilla-org
Lifecycle state recorded: 12 Sep 2026
Verification state: Indexed for public listing
Listing state: Listed: yes
Index status: Included in index
Latest evidence snapshot: 12 Sep 2026
Timeline basis: Indexed-at chronology (no inferred launch/funding milestones).
Name from: Derived from the project's own page and URL.
Category from: Assigned by a language model.
Summary from: Written by a language model from public pages.
Languages from: Detected by a language model, checked against the page's own declaration.
Last updated: 12 Sep 2026
Canonical URL: https://addons.mozilla.org/en-US/firefox/addon/user-js-and-css

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