Move a stick, then let it rest
Connect a controller and press a button to make it visible to the browser. Raw values are shown beside values remapped through the selected dead zone. The stick plots use the first two axis pairs. Leave the sticks untouched and sample their resting positions to compare the raw range with the selected dead zone.
A worked example
With a dead zone of 0.10, an axis at 0.05 maps to 0. An axis at 0.55 maps to 0.50 using (0.55 − 0.10) ÷ (1 − 0.10).
Before you use the result
A value outside the dead zone is an observation, not a fault diagnosis. Button mapping and browser support vary. Connect a controller before interpreting the readings.