## TL;DR

The Pointer Lock API (`element.requestPointerLock()`) captures mouse movement for games and 3D applications, hiding the cursor and providing raw movement data (`movementX`, `movementY`) without screen-edge boundaries.

## Core Explanation

`document.pointerLockElement` returns the locked element or null. `pointerlockchange` and `pointerlockerror` events fire on state changes. Mouse movement deltas are unbounded — ideal for first-person camera controls. Escape key exits pointer lock. Typically combined with `document.addEventListener('mousemove', handler)`.

## Further Reading

- [Pointer Lock (W3C Recommendation)](https://www.w3.org/TR/pointerlock/)