# Script Blocker — Block Third-Party Scripts

> Block third-party scripts that slow down pages without touching login flows or payment forms, at three coverage levels.

- Canonical: https://www.superchargebrowser.com/features/script-control/
- Extension: performance
- Published: 2026-03-13
- Updated: 2026-08-07
- Source: SuperchargeBrowser (https://www.superchargebrowser.com)

Script Control blocks JavaScript files loaded from external domains — the widgets, analytics libraries, and tracking beacons that often make up a large share of a page's load weight. By stopping these scripts before they execute, pages parse faster, the main thread stays less congested, and you reduce exposure to third-party code you never agreed to run.

## How It Works

When your browser loads a page, it frequently fetches JavaScript from dozens of domains other than the site you are visiting. Script Control uses Chrome's **declarativeNetRequest API** with three static rulesets to intercept script requests that originate from third-party domains.

The rulesets are layered — each higher level activates the rules from the level below plus an additional set targeting a broader category of third-party scripts. The extension evaluates requests at the network layer before they download, so blocked scripts never execute and never consume CPU time parsing or running.

## Settings

| Level | What Gets Blocked                                                              | Availability |
|-------|--------------------------------------------------------------------------------|--------------|
| Low   | Analytics and tracking scripts — nothing user-visible changes                  | Free         |
| Med   | Adds social and video embed scripts (share buttons, comment systems) — embedded YouTube/Vimeo players, Disqus comments, and Facebook Login stop working | Free |
| PRO   | All third-party scripts except login providers and payment processors          | PRO          |

The default is **Low**. This blocks analytics and tracking without touching anything visible on the page. Move up to Med if you want embedded widgets blocked too and don't mind them breaking.

## When to Use This

- Pages feel slow to become interactive even on a fast connection — third-party scripts often block the main thread during parse
- You want to reduce CPU usage on pages with many embedded widgets or analytics tools
- You are on a shared or throttled connection and want to minimize unnecessary downloads
- You use PRO and want the most aggressive script reduction while keeping payment and login flows working

Pair Script Control with [Ad Blocking](/features/ad-blocking/) for layered coverage: ad blocking removes known tracker domains, script control removes the broader third-party script surface.

## Privacy

Script Control operates entirely locally using static rules bundled with the extension. No page content, script URLs, or browsing data is transmitted to any server. All rule matching happens inside Chrome on your device.

---

Canonical URL: https://www.superchargebrowser.com/features/script-control/