# JavaScript Permission Matrix

> This extension allows you to control JavaScript API permissions at per-script basis.

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

## Overview

- **ID:** `js-permission-matrix`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Anon
- **Category:** privacy-security
- **Daily users:** 1
- **Rating:** 3.67 / 5 (3 ratings)
- **Version:** 1.8.3.7
- **Last updated:** 2026-06-20
- **First published:** 2019-09-17
- **Size:** 71 KB
- **Data as of:** 2026-09-11
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/js-permission-matrix/)

## Description

This extension lets you manage permissions for the use of JavaScript APIs both for entire sites or pages and for individual scripts. You can choose a combination of a script or page address together with an API name or some specific JavaScript functionality, and configure the permissions you consider necessary for that combination.

Example: on the same web page there are 2 different scripts. One allows you to edit images via the Canvas API. The other uses the same Canvas API to perform fingerprinting. The browser’s built-in mechanisms won’t let you allow Canvas to the first script and block it for the second. This extension will allow you to do that.

TL:DR; this extension may do the same things as WebAPI Manager or Web API blocker, but at per-script basis.

## Rankings

- #73,105 — Overall
- #34 — permission
- #44 — javascript
- #47 — permissions
- #200 — script
- #238 — mission

## Permissions and access

### Permissions

- `<all_urls>`
- `activeTab`
- `storage`
- `tabs`
- `unlimitedStorage`
- `webRequest`

## Safety

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

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- 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/js-permission-matrix)