How to use this test
Start motion
Choose Start motion and watch the moving block.
Look for smooth movement
Notice pauses, stutter or missing motion in this browser window.
Compare if needed
Try another browser or application before treating a difference as hardware failure.
What we check
The page draws a moving pattern with the browser animation frame API.
Visible motion shows that this page is currently drawing frames in the browser window.
What this test can’t tell you
It is not a video-codec test, frame-rate measurement, monitor refresh-rate test or performance benchmark.
Something not working?
The pattern does not move
Check reduced-motion settings, browser extensions and whether the page is in a background tab.
The motion looks uneven
Background activity and browser scheduling can affect page animation. Compare another app or browser.
Common questions
Does this play a video file?
No. It draws a local motion pattern rather than downloading or decoding a movie file.
Can it measure refresh rate?
No. Browser animation timing is not a monitor measurement.