# Custom Site JS

> Run your own (per url or domain) custom JavaScript on sites.

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

## Overview

- **ID:** `custom-site-js`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** David Hicken
- **Category:** web-development,appearance
- **Daily users:** 216
- **Weekly downloads:** 3
- **Rating:** 4.57 / 5 (7 ratings)
- **Version:** 1.0.1
- **Last updated:** 2019-10-29
- **First published:** 2019-10-29
- **Size:** 98 KB
- **Data as of:** 2026-09-25
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/custom-site-js/)
- **Privacy policy:** [https://addons.mozilla.org/firefox/addon/custom-site-js/privacy/](https://addons.mozilla.org/firefox/addon/custom-site-js/privacy/)

## Description

Custom Site JS is a Firefox add-on that enables you to easily run personalized JavaScript on websites as they load. With the ability to add, edit, or delete JavaScript snippets based on URL, you can customize websites to your liking. The extension operates locally, ensuring your information remains secure.

## Rankings

- #8,053 — Overall
- #23 — site
- #24 — custom feed
- #25 — custom font
- #30 — customer
- #64 — javascript

## Permissions and access

### Permissions

- `webNavigation`
- `storage`
- `tabs`
- `*://*/*`

## Safety

- **Risk impact:** High risk impact
- **Risk likelihood:** Low 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/custom-site-js)