Browser `windowmove` event

windowmoveevent.js

(function() {
  let screenX = window.screenX;
  let screenY = window.screenY;

  function update() {
    const movementX = window.screenX - screenX;
    const movementY = window.screenY - screenY;

    if (movementX != 0 || movementY != 0) {
      screenX = window.screenX;
      screenY = window.screenY;

      const event = new Event("windowmove");

      event.movementX = movementX;
      event.movementY = movementY;
      event.screenX = screenX;
      event.screenY = screenY;

      window.dispatchEvent(event);
      typeof window.onwindowmove == "function" && window.onwindowmove(event);
    }

    window.requestAnimationFrame(update);
  }

  window.requestAnimationFrame(update);
})();