Custom JavaScript for Websites 2

Run custom JavaScript on any website.
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Custom JavaScript for Websites 2 lets you inject your own JavaScript code into any website for enhanced customization and debugging. Scripts are synced across your Chrome profile, and you can target injection by domain or regular expression patterns.

The extension supports popular built-in libraries like multiple jQuery versions, MooTools, and Indefinite Observable. It includes a dedicated script editor with Ace Editor features such as syntax highlighting, formatting, undo/redo, and draft auto-save. Use cases range from fixing UI bugs, extracting data, hiding ads, to building completely custom user interfaces, making it a powerful tool for developers and power users alike.

Manifest V2 Developer Tools Productivity Programming
By:
xcv58
Users:
40,000+
Rating:
4.37
(131)
Version:
3.4.12 Last updated: 2023-02-20
Creation date:
2020-04-28
Risk:
High risk impact Low risk likelihood
Permissions:
  • storage
  • http://*/
  • https://*/
  • tabs
Size:
602.11K
Email:
ch*****@xcv58.com
Full description:
See detailed description
Source:
Chrome Web Store
Updated:
a day ago

Ranking

# 3,738 ▼ 67
Other rankings
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User reviews

Users appreciate the extension for its simplicity and effectiveness in injecting custom JavaScript, making workflows easier. However, multiple reviews mention limitations such as script size restrictions, lack of automatic script execution, and failures on sandboxed pages like YouTube. Some users express concern about the extension becoming unsupported, while others highlight its superiority over similar tools. Overall, it's valued but has notable limitations impacting usability on certain sites and with large or special character-containing scripts.
Pros
  • Allows easy injection of custom JavaScript into websites
  • Simplifies adding scripts like jQuery directly within the extension
  • Reliable and effective for many websites, making user tasks easier
  • Praised for being a time-saving and user-friendly tool
  • Successfully used by long-term users who rely on it regularly
Cons
  • Limited script size due to storage.sync constraints causing save failures with large scripts
  • Does not work on certain websites with sandboxed frames (e.g. YouTube) due to security restrictions
  • Requires manual script activation each time; no option for automatic script execution on page load
  • Incompatibility or issues with handling special characters in scripts (e.g., accented characters)
Recent reviews
Please please update your extension! It's no longer supported! :'(
by Endre Varga, 2025-03-08
Epic!
by Byte Afterlife (Byte), 2025-01-18
Doesn't work on every website. You'll get "Blocked script execution in 'about:blank' because the document's frame is sandboxed and the 'allow-scripts' permission is not set." on YouTube when trying to access the document.
by NotAHackusator, 2024-10-31
View all user reviews ›

Extension safety

Risk impact

Custom JavaScript for Websites 2 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.
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  • High ******* ******* **** *** ****** ***** *** ***** ** ******* **** ********* ********* ** * *********** *****
Risk likelihood

Custom JavaScript for Websites 2 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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Upgrade to see full risk analysis details

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