Keyboard ghosting & rollover test.
Hold several physical keys at once to see which combinations reach your browser.
Try holding W, A, Shift, and Space together.
What is keyboard ghosting?
A keyboard scans a matrix of switches. On some keyboards, particular combinations cannot be distinguished reliably. Ghosting can produce phantom inputs; key blocking can prevent some pressed keys from registering. This page shows the events that actually reach your browser.
How to check rollover
Hold a group of keys that you use together in a game or application. Count the physical keys you are holding, then compare that count with the displayed keys. Repeat with different combinations. A peak count describes this session, not a certification of your keyboard’s full rollover capability.
Browser limitations
Fn, operating system shortcuts, and some media keys may never reach a website. Losing focus clears the held list. If a key is missing, compare results in another application before concluding there is a hardware problem.