This extension protects against web pages tracking the activity state of the page. Some websites use this track to only offer services when the tab is active. By installing this extension a small script is injected into every webpage which overwrites the "document.visibilityState", and "document.hidden" properties to pretend the tab is always in the active state (document.visibilityState = 'visible' and document.hidden = false).
It also suppresses DOM event paths that can expose a transition to another app: focus/blur and focus-boundary events, visibility changes, page hiding, pointer capture loss, and mouse/pointer boundary events caused by moving onto an external overlay. Configure keyboard events to block from the options page using a KeyboardEvent.key, KeyboardEvent.code, or numeric keyCode value; AltGraph is blocked by default. A hostname policy can opt out with "keyboard", "mouseleave", or "mouseout".
The options page has mouse re-entry controls. Humanize ranges from 0–1 and adds a bounded randomized curve and slight timing variation. Interpolation at 0 leaves mouse movement immediate; higher values make generated mouse and pointer move events follow a smooth curve through buffered positions more slowly after the browser loses focus. Interpolation ranges from 0–1, while start and stop smoothness range from 0–2. When another app covers the browser without sending an exit event, a pause in mouse input followed by a distant move starts the same smoothing from the last position seen by the page. Start and stop smoothness control acceleration and braking. The defaults are 0.5 humanize, 0.35 interpolation, 0.3 start smoothness, and 0.3 stop smoothness. A second return joins the unfinished path in order. A mouse click ends interpolation and moves the generated cursor position to the click. Native movement resumes when the generated cursor catches up.
By default, the extension is enabled on all sites. The options page can switch to an opt-in hostname list; in all-sites mode, the hostname list is a set of exceptions.
node --test test/*.test.js
node scripts/test-browser-interpolation.mjs
npx --yes web-ext@10.5.0 lint --source-dir v3
npx --yes web-ext@10.5.0 build --source-dir v3The browser interpolation test drives real Chrome mouse input through the injected script. Set TEST_UNPACKED=1 to load and test the unpacked extension through Chrome DevTools, including its content script registration. Add TEST_SITE=1 to test the DPIonMouse movement canvas directly; this requires network access. Add TEST_CANVAS_ONLY=1 to verify that leaving just the canvas does not interpolate, TEST_OVERLAY=1 to verify that a DOM overlay does not interpolate, TEST_OS_OVERLAY=1 to test an in-canvas return after a quiet overlay gap, TEST_SECOND_ENTRY=1 to test two focus returns in order. Set TEST_SETTINGS=1 to measure each slider's effect in Chrome. Set CHROME_BIN to a Chromium-based browser binary if Chrome is installed elsewhere.
To create a Chrome-compatible MV3 build and ZIP package:
node scripts/build-chrome.mjsThe unpacked extension is written to dist/chrome; load that directory through
Chrome's Extensions page with Developer mode enabled. The corresponding ZIP
is written to dist/packages for Chrome Web Store upload.
Tagged versions are validated, submitted to Firefox Add-ons, and attached to a GitHub Release automatically. See Firefox release setup.
Always Active Plus is released under MPL-2.0.