How to use: Keyboard Chatter Test
Arm the lab and press the target key once so its physical code is selected.
Make at least 30 slow, deliberate single presses without holding the key.
Review suspicious intervals, then repeat with another connection or keyboard before repair.
What the result actually measures
The test records non-repeat keydown timestamps for one selected physical code, calculates inter-press intervals and flags events inside the chosen chatter window. Held-key repeat events are counted separately instead of mislabeled as switch bounce.
Measurement boundary: Fast intentional taps can look like chatter, and a browser cannot identify the physical switch cause. Use slow deliberate single presses and confirm on another port/device.
How to interpret the output
Suspicious interval
Two non-repeat down events delivered within the selected short window after deliberate single presses.
Held repeats
Events marked repeat by the browser; normal while a key remains held and excluded from chatter flags.
Repeatability
A pattern on the same key across slow sessions is more useful than one isolated event.
Troubleshooting unexpected results
Every fast tap is flagged
Slow the physical rhythm or lower the warning window; the page cannot infer intent from timing alone.
Only a shortcut key fails
The browser or operating system may reserve it. Test the physical key alone and use an OS utility for confirmation.
Frequently asked questions
Is chatter the same as key repeat?
No. Key repeat is expected while held; chatter is an unintended additional actuation around a deliberate press.
What window should I use?
Start with the conservative 35 ms screen and repeat at another threshold if the pattern is ambiguous.
Are key presses stored?
No. The active code and timing session remain in the page.