1·Earlier, I mentioned that there were two major interactivity elements in the Swappable system: highlighting the dragged element and highlighting the drag target.
前面，我提到过在可切换系统内有两种主要的交互元素：拖动元素的突出显示和拖动到的目标的突出显示。
2·This handler is responsible for moving the translucent rectangle that represents the element being dragged.
此处理程序负责移动代表被拖动元素的透明矩形。
3·This is how the drag-and-drop capability of the map comes to life — when the map is dragged, the server sends the image for the area you are requesting, and the map loads it immediately.
这就是实现地图拖放功能的方法——在拖动地图时，服务器发送用户请求的地区的图像，地图立即装载它。
4·This object can be queried as to the nature of the data being dragged.
可向该对象查询被拖动的数据的类型。
5·You pass the current cursor coordinates to the dragger, and it updates the dragged object to move along with the cursor.