What it is
The screen object reports the display’s resolution, the area left after the taskbar or dock, the colour depth and the device pixel ratio. The window object adds the inner and outer size of the browser window. None of it needs permission.
How websites read it
screen.width + '×' + screen.height // "2560×1440"
screen.availWidth + '×' + screen.availHeight // minus taskbar / dock
window.devicePixelRatio // 2
screen.colorDepth // 24 or 30The values are read in one line each. Their relationships are what matter: available ≤ screen, inner window ≤ outer window ≤ screen (multi-monitor setups excepted), and a pixel ratio that fits the device class.
Why it identifies you
Resolution alone is shared by millions, but combined with pixel ratio, colour depth and the exact available height (which encodes taskbar size and OS version) it becomes a solid component of the fingerprint. It is also very stable.
How risk-control systems use it
Impossible geometry is a hard flag: an available area larger than the screen, a window larger than the display, a 30-bit depth on a device that cannot have it. Plausibility rules come next — a 4K desktop resolution on a phone UA, or the same odd resolution across many accounts.
Common mistakes
Setting screen.width and height without recomputing availWidth and availHeight; resolutions that exist on no shipping panel; a retina pixel ratio on a Windows UA; a maximised window that is larger than the screen it claims.
Mango is accepting waitlist registrations. These capabilities describe its first release; client access opens with invitations.
How Mango Browser handles it
CustomChosen from 42 common resolutions per OS; the available area and window size follow from it so the geometry always adds up.
Check yours
Jump to this signal in your scan results.