Javascript Firewall Firefox

Javascript Firewall

By: Bill
Block JavaScript of unwanted origin.

Features & Capabilities

This extension is intended for advanced users. Some websites will require configuration to work properly.

For each website, you can decide from which domains JavaScript is allowed. By default, only scripts from the same domain than the website are allowed.

Interface

  • The table shows how many requests have been blocked or allowed on the web page for each domain. Each column of the table represents a type of request:
    • JS: javascript code: <script> and Workers
    • XHR: data request: XMLHttpRequest, Fetch, WebSocket, Beacon, ping, and Content-Security-Policy-report
    • FRAME: external content: <iframe>, <frame>, <object> and <embed>
    The color of a cell indicates whether it has been blocked or allowed :
    • dark red: blocked explicitly
    • light red: blocked by a more general rule
    • light green: allowed by a more general rule
    • dark green: allowed explicitly
    To create a rule, click on a cell until you get the desired color.
  • The drop-down list at the top left indicates on which websites the rules apply. By default, a rule only applies to the website's domain and it's subdomains. If you want to create a rule that applies to all websites, select "all websites".
  • The 5 buttons:
    • Reload: For the new rules to take effect, the page must be reloaded.
    • List: Manage the settings and the rules you have created. You can use the text mode to manually edit your rules (4th screenshot)
    • Disable/Enable: When disabled, the addon will not block anything for the current tab but will still count requests.
    • Delete: Delete the rules you have created for the current website.
    • Arrow: Display all the parent domains. It makes it possible to create a rule which will apply to all its subdomains.
  • The badge on the icon shows the number of blocked requests.
Examples
  • Make Youtube works (1st screenshot)
    1. Go to a Youtube video and click on the addon icon
    2. Click on the arrow button to display the parent domains
    3. Allow XMLHttpRequest (XHR) for googlevideo.com
    4. Reload the page
  • Allow embedded YouTube videos on all websites (2nd screnshot)
    1. Go to a Youtube video
    2. Click on the arrow button to display the parent domains
    3. Select "all websites" in the drop-down list
    4. Allow JS, XHR and FRAME for www.youtube.com and XHR for googlevideo.com
  • Allow everything for a website (3rd screenshot)
    1. Make the "JS", "XHR" and "FRAME" cells dark green
Other examples can be found on the wiki.

Limitations The extension does not work on domains listed in the preference "extensions.webextensions.restrictedDomains", mainly Mozilla websites such as https://addons.mozilla.org

GitHub https://github.com/billdoor1/javascript_firewall

User Growth & Download Statistics

Manifest V2 Add-on
By:
Bill
Daily users:
6
Rating:
4.38
(16)
Version:
1.4 Last updated: 2022-05-10
Version code:
5402699
Creation date:
2019-09-30
Risk:
High risk impact Low risk likelihood
Permissions:
Size:
17.15KB
URLs:
Website
Full description:
See detailed description
Source:
Firefox Add-ons Store
Data ingested on:
2026-06-15
Compare stats and ranking:

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.
Developed by:
Bill
Firefox Add-ons Store
https://addons.mozilla.org/firefox/addon/javascript-firewall/
Website:
https://github.com/billdoor1/javascript_firewall/issues

User Reviews

Very nice tool against trackers and attackers. It also really highlights how much websites try to get away with in the background.
by hj*****, 2026-03-03

by 远离*****, 2025-04-15

by 远离*****, 2025-03-09
View all user reviews ›

Is Javascript Firewall Safe?

Risk impact
Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Javascript Firewall requires some sensitive permissions that could impact your browser and data security. Exercise caution before installing.

Risk impact analysis details
  • Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
  • High ****** *** ********* ** ******* *** ******* ******* ** ****** *** *** ******** ******
  • High ****** ********* ** * ****** ******** ******** ********** * ******* ******* *****
Risk likelihood
Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

Javascript Firewall has earned a fairly good reputation and likely can be trusted.

Risk likelihood analysis details
  • High This extension has low user count. Unpopular extensions may not be stable or safe.
  • Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
  • Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
  • Good **** ********* *** **** **** *******
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