document.hidden agrees with document.visibilityState
document.hidden is true exactly when document.visibilityState is "hidden" — always, by definition.
What a detector infers
document.hidden and document.visibilityState are two views of one piece of state, and the specification defines the first in terms of the second: hidden is true exactly when visibilityState is the string "hidden". There is no state of a real browser in which they disagree, because one is computed from the other.
This is worth checking because faking foregroundedness is a common and rational thing for automation to do — browsers aggressively throttle timers and rAF in background tabs, which slows a headless run to a crawl, so tooling patches the page into claiming it is visible. And when it does, it tends to patch the property a page is most likely to read while missing its twin. A detector needs no baseline to notice: it reads both and asks whether they can both be true.
How to resolve it
Never patch one of these without the other; the spec derives hidden from visibilityState, so a disagreement is not an unusual browser but an impossible one. If the goal is to escape background throttling, keep the page genuinely foregrounded — or accept the throttling — rather than claiming a visibility the browser is not in.
Read in the wild by
Kasada
Reads both halves of the visibility state, which are defined in terms of each other.
document_hidden, document_visibility_state
Kasada ips.js teardown — the full 427-probe listEvery attribution traces to a published artifact. See the sources and their limits.
Nearby checks in Automation surface
- timer handles are a real per-realm counter
timer-id-sequencingThe number setTimeout hands back is not a token, it is an index into the realm's own timer table — so it carries structure that a fabricated… - the media-session counter runs forward and does not restart
eme-session-counter-monotonicA deployed commercial agent opens a ClearKey media session purely to read its identifier as a number — and then, if that number comes back… - the global object carries every platform global its claimed Chromium major carries
window-globals-vs-baselineThe list of names on the global object is not written by the page — it is installed by the engine when it sets up a realm, from a table… - the element prototype chain matches its claimed Chromium major's
element-surface-vs-baselineA for..in over the document element does not enumerate one object: it walks the whole prototype chain — HTMLElement, Element, Node… - navigator.plugins is a real IDL collection, not a JavaScript object
plugins-idl-index-wraparoundA real navigator.plugins is a PluginArray — a C++-backed IDL collection — and its indexed getter runs the Web IDL unsigned-long conversion… - navigator.storage quota is the same in the window and a same-origin worker
storage-quota-worker-vs-mainnavigator.storage.estimate().quota describes one storage partition, and a same-origin worker shares that partition — a single QuotaManager… - performance.timeOrigin + performance.now() reconstructs Date.now()
clock-origin-coherenceA page has two clocks. performance.timeOrigin is the wall-clock moment its timeline began; performance.now() is the monotonic time elapsed… - the gesture that started this audit registered as a real user activation
user-activation-vs-interactionThis audit only runs when you press the Run button, and pressing a button is exactly what grants user activation — by pointer, by Enter or…
Clearcote is a browser built for fingerprint coherence
It is a Chromium fork, maintained by the same people who wrote this reference. It ships as a compiled browser rather than as a stealth script injected into someone else's — which is a description of how it is built, and is not an argument about how it behaves on this check.
This audit takes no position on how Clearcote scores on Automation surface checks, on this one, or anywhere else. It has no baseline corpus of other people's fingerprints to rank you against and no vendor scoreboard — nearly every check is self-referential, asking one browser the same question through two independent APIs and reporting whether both answers can be true at once. It runs identically on any browser, including ours. Run it on yours and read the result yourself.
See the other checks in Automation surface — the family document-visibility-coherence belongs to.