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product / anti-blur

Anti-Blur

Sites stop knowing the moment you look away. Websites that dim, pause or log the moment you switch tabs are told nothing happened.

v1.1.0Chrome extension · Free

Download Anti-Blur →Read the docs

Anti-Blur’s popup: a green ON badge, www.example.com with its switch on, the line “Anti Blur on for this site”, and the shortcut that toggles it.

Anti-Blur · the popup

what it does

What every page is told

Four properties, one answer

Switch tabs, click into another app or move the pointer off the page and most sites can tell. Anti-Blur answers document.hasFocus(), document.hidden and visibilityState as though you never left, and never delivers the blur and visibilitychange events that would say otherwise.

What that looks like

Videos keep playing when you switch tabs, and nothing dims or asks if you are still there. Attention analytics get a flat line. In a background tab Chrome itself slows timers to about once a second; animation loops keep stepping at that pace instead of stopping.

“Blur” is the browser’s word, not the camera’s

A blur event is what a page receives when it loses focus. Nothing here sharpens an image.

What it cannot do

  • It cannot stop a site that measures something else. A page watching request timing or frame rate can still infer a great deal.
  • It does not block ads or trackers. That is Sodium.
  • It does not stop a site recording your screen. That is Perch.
  • It cannot make a background tab run at full speed. Chrome slows a hidden tab’s timers to about once a second, and after five minutes to about once a minute. Anti-Blur keeps the page from knowing; it cannot lift the limit.
  • A page that asks whether its own input still matches :focus can still tell the window lost focus.
Permissions
Access to the pages you visit — the script has to run on them, before their own — plus scripting and storage. No network access.
Stored
The sites you turned it off for, in your browser. Nothing else.
Interface
A popup with an on/off switch for the site you are on, and Alt+Shift+B for the same.
Terms
Its own Terms and Privacy Policy.
Price
Free — download it

Getting Anti-Blur

Free, and a download of its own — never a Chrome Web Store listing. Take the zip from the download page, unzip it, then open chrome://extensions, turn on Developer mode and press Load unpacked on the folder. That runs on your everyday profile and survives a restart.

Download Anti-Blur →Which extension do I want?