Measure signals. Explain uncertainty.
Keyboard tests read keydown and keyup events. Held-key auto-repeat is excluded from the repeat counter. Rapid event pairs are flagged using your selected threshold; the flag is not an electrical diagnosis. Layouts are generic representations and system shortcuts may be intercepted.
Audio levels are calculated from digital samples as RMS dBFS. They do not measure acoustic loudness. Recordings use the browser’s available encoding and may include its audio processing. Camera resolution is the delivered frame size, not a certified sensor specification.
Screen tests provide visual patterns. You inspect them and record your observation. Gamepad values come from the Gamepad API without firmware calibration. Touch cells mark received pointer events and distinguish touch from mouse input.
Reports preserve user observations, not automatically awarded pass/fail certificates. To isolate a fault, repeat under the same conditions, change one factor at a time and compare with a known-working device. Reference documentation: MDN Web APIs.