Feature: block external JavaScript

[multimeric]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality by using the chat icon in the popup panel.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO Lite in the browser.

I tried to reproduce the issue when...

• uBO Lite is the only extension.
• using a new, unmodified browser profile.

Description

This is a feature request, not a bug report. It's not clear where these should go.

uBlock Origin for manifest v2 had the option to disable JavaScript for a page. This functionality doesn't seem to have made it to uBOL. However, I think it can still fit nicely within the declarative design of uBOL. It seems that you can use "resourceTypes": ["script"] to block external scripts under manifest v3. I understand that this wouldn't stop inline JavaScript, but I suspect it would help in a majority of cases where the offending JavaScript is external.

A specific URL where the issue occurs.

https://www.theage.com.au/

Steps to Reproduce

1. Go to a page
2. Open the extension window

Expected behavior

As in uBlock Origin, there should be a "disable JavaScript" option

Actual behavior

No such option exists.

uBO Lite version

2025.711.1256

Browser name and version

Chrome 138.0.7204.100

Operating system and version

Ubuntu 22.04

[gorhill]

The main issue with a uBO-equivalent switch in MV3 is that it's currently not possible to have network rules which depends on top level context, which is how it works in uBO.

However there is a proposal to add this ability: w3c/webextensions#762

If this becomes available it will become possible to implement a JS toggle as in uBO. When this happens I will re-assess if I want to go forward with this, and how while being very careful to not bloat the user interface with features not actually used by a majority.

[multimeric]

Is blocking based on the initiator domain not a reasonable solution in the meantime?

[gorhill]

The expectation with using a JS toggle switch is that it propagates to all embedded contexts.

This would be an issue if trying to make an embedded Youtube video work for example, as there would be no way to enable JS in embedded contexts while keeping the popup panel UI simple as it is now. The workaround would be to visit directly the site which is embedded, than toggle the switch, than go back to the page with the embedded context, force a reload. Quite inconvenient and difficult to explain such way of working.

I prefer to waiting for the capability rather than an half working solution. And as said, when the capability becomes available, I will re-assess whether I want to add this feature to uBOL. If so, it's probably going to be something like an opt-in tool to add to the popup panel.

[gorhill]

topDomains as a condition has become available in Chromium 145: https://developer.chrome.com/docs/extensions/reference/api/declarativeNetRequest#property-RuleCondition-topDomains.