Tampermonkey Script Activation Guide for Chrome, Opera, and Edge

Due to new security policies (Manifest V3) in Chromium-based browsers (Chrome, Opera, Edge), manual approval is required for userscripts to run. If your scripts work in Firefox but remain inactive in these browsers, follow the steps below.

🛠️ Solution Steps

1. "Allow User Scripts" Setting (New)

According to the official Tampermonkey (v5.3+) announcement, the browser must explicitly grant the extension permission to execute code:

  • Right-click the Tampermonkey icon in your browser.
  • Select "Manage Extension".
  • Scroll down to find the "Allow User Scripts" toggle and switch it ON.
  • Note: This setting is mandatory for Chrome/Edge 138+ and recent Opera versions.

2. Enable Developer Mode

Google requires this mode to be active for extensions to utilize the userScripts API:

  • Enter the appropriate address for your browser in the address bar:
    • Chrome: chrome://extensions
    • Opera: opera://extensions
    • Edge: edge://extensions
  • Switch the "Developer Mode" toggle in the top right corner to ON.
  • It is recommended to restart your browser for the changes to take full effect.

3. Extension Permissions and Access Control

  • Go to the "Details" section of Tampermonkey in the extension management page.
  • Enable the "Allow access to file URLs" option.
  • Ensure that the Site Access setting is set to "On all sites".

4. Additional Settings for Opera Users

Opera's built-in features may block scripts:

  • Ad Blocker: Click the blue shield icon in the address bar and disable the blocker for the specific site.
  • Battery Saver: Go to browser settings (Alt + P) and turn off "Battery Saver"; this mode may suspend background scripts.

🔍 Technical Explanation & Source

As stated in the official Tampermonkey FAQ (Q209), Google has implemented a "two-step authorization" process to prevent code from running without explicit user consent. Simply installing the extension is no longer enough; the user must either enable Developer Mode or manually trigger the "Allow User Scripts" toggle in the extension settings.

Official Source: Tampermonkey FAQ - Q209: Permission to execute userscripts

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Pub: 06 Apr 2026 19:08 UTC

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