gsap.registerPlugin(Draggable)

const myDraggable = Draggable.create('#box', {
  bounds: '#container'
})[0]


myDraggable.addEventListener('press', onPress)

function onPress() {
  console.log('pressed', this) // this 表示 draggable实例
  // this.target 表示被拖动的元素
  gsap.to(this.target, { duration: 2, backgroundColor: 'purple' })
}