icon128Sybu JavaScript Blocker is a Google Chrome Extension to quickly block JavaScript (JS) files from being loaded by the browser.

It has been designed to be easy to use.



Install from Google Chrome Web Store


After you have installed the extension.  It will be visible to the right of the Chrome search/address bar.


It is a little Blue Shield icon or Blue Sybu icon depending if it is new install or update. Click the icon.


The Sybu JavaScript Blocker has 3 modes:  OFF | My Rules | Block All


Mode:  Off

The extension is disabled and will not block any JavaScript files

Mode: My Rules

In this mode the extension will block or allow JS files based on the rules specified in Block Rules and Allow Rules

User Interface


sd_jsblock_120_06b JavaScript file was allowed and loaded. No rule was applied.

 JavaScript file was allowed and loaded, based on Allow Rule.

sd_jsblock_120_06cJavaScript file was blocked, based on Block Rule

1,2,3.. The numbers next to listed items indicated the processed sequence

sd_blocker_indicator The total number of files blocked.  Click to sort.


 Click to edit the Block Rules

 Click to edit the Allow Rules


File is currently allowed.  Click to add Block Rule

File is currently allowed. Click to remove Allow Rule

 File is currently blocked. Click to remove Block Rule

 File is currently blocked.   Click to add Allow Rule


Block Rules

Click the  button, to show the setup

Block Scripts from 3rd party domains.

When enabled,  the script will block JavaScript files that are not from the same domain as as the requested page.  This will immediately block a lot of trackers and advertising links, without the need to specify individually.  In the example below you will notice when this option is enabled any script not from the sybu.co.za domain was blocked.

Additional block rules can manually be entered. These can be complete URLs, or any part of, as shown below

Rules can also be added by clicking on the indicator

In this example if you choose

1: gpt – This will block any JavaScript on any page that contains gpt as part of the URL

2: gpt.js – This will block the JavaScript with filename gpt.js on any page

3: https://www.googletagservices.com/tag/js/gpt.js    – This will block JavaScript file originating from https://www.googletagservices.com/tag/js/gpt.js

4: www.googletagservices.com   – This will block any Javascript originating from domain www.googletagservices.com

5: Other.  This will block any JavaScript on any page that contains the specified text as part of the URL

To unblock a file (and remove the rule associated with it) click on the [-] button next to the file being blocked.
or simply remove the text from list of items in Block Rules


Allow Rules

Click the  button, to show the setup

NOTE: An Allow Rule will override a Block Rule.

The setup of Allow Rules is similar to Block Rules. Simply add a list of items (full domain names, or partial file names).


 Mode: Block All

In this mode all JavaScript will be blocked, but you will find that most pages do not render properly.  So options are available to allow some JavaScript to be loaded. Exceptions can be added in Allow Rules.   

So for example it may be useful not to block a script like jquery since this is used on many websites to display content dynamically.







icoSetupHelpbugPlease complete form below to ask a question or submit a bug.

    * Your Name

    * Your Email

    * Bug Report or Feature Request