TOP-
LEFT
TOP-
RIGHT
BOTTOM-
LEFT
BOTTOM-
RIGHT
UP (doc top)

Live environment (refresh 1s)

window.inner W×H:
screen W×H:
screen.avail W×H:
devicePixelRatio:
documentElement client W×H:
visualViewport W×H:
orientation.type / angle:
aspect ratio (W/H):

navigator.userAgent

Timers & animation

setInterval ticks: 0

Inline video autoplay

video: waiting…

Font & colour test card

Arial 48px — The quick brown fox 0123456789
font-family: Arial; 48px
Times 40px — The quick brown fox 0123456789
font-family: 'Times New Roman'; 40px
Courier 32px — The quick brown fox 0123456789
font-family: 'Courier New'; 32px
Verdana 28px — The quick brown fox 0123456789
font-family: Verdana; 28px
Georgia 20px — The quick brown fox 0123456789
font-family: Georgia; 20px (smallest test — readable at 3-4m?)
R #f00
G #0f0
B #00f
WHITE #fff
BLACK #000
GRAY #808080

Diagnostics capture

base64 of JSON (manual transcription fallback):
QR: scan with a phone to capture diagnostics