# Inject Custom JS and CSS

> Inject custom JavaScript and CSS code into any webpage

Canonical page: [https://chrome-stats.com/d/inject-custom-js-and-css](https://chrome-stats.com/d/inject-custom-js-and-css)

## Overview

- **ID:** `inject-custom-js-and-css`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Iván Ros
- **Category:** web-development
- **Version:** 1.0.0
- **Last updated:** 2026-02-28
- **First published:** 2026-02-25
- **Size:** 23 KB
- **Data as of:** 2026-09-12
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/inject-custom-js-and-css/)

## Rankings

- #139,890 — Overall
- #82 — inject

## Permissions and access

### Permissions

- `storage`
- `tabs`
- `activeTab`
- `<all_urls>`
- `webNavigation`

## Safety

- **Risk impact:** High risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/inject-custom-js-and-css)