Why JavaScript Cannot Accurately Measure Your Mouse's True Polling Rate

Gaming mice can operate at polling rates of 1000Hz, 4000Hz, or higher, but JavaScript in a browser cannot directly read this hardware value. Instead, it only sees pointer events that have already passed through the operating system and browser event-processing layers. Browsers also use a technique called event coalescing, which combines multiple rapid pointer updates into fewer dispatched events to reduce processing overhead, causing measured rates to appear lower than actual hardware rates. The W3C Pointer Events specification explicitly permits this coalescing behavior, meaning JavaScript callback frequency does not equal mouse hardware report frequency. A newer browser event called pointerrawupdate is designed to fire more frequently and with less delay than standard pointermove events, though it still does not provide a direct readout of the underlying hardware polling rate.