function cnvs_getCoordinates(e){x=e.clientX;y=e.clientY;document.getElementById("xycoordinates").innerHTML="Coordinates: (" + x + "," + y + ")";}為什么非要傳個參數,有什么好處,下面這么些有什么不同?function cnvs_getCoordinates(){x=event.clientX;y=event.clientY;document.getElementById("xycoordinates").innerHTML="Coordinates: (" + x + "," + y + ")";}