没有没大佬 讲讲方法？

/** 开始移动*(x坐标, y坐标,持续时间)*/
Sprite_Battler.prototype.startMove = function(x, y, duration) {
if (this._targetOffsetX !== x || this._targetOffsetY !== y) {
this._targetOffsetX = x;
this._targetOffsetY = y;
if (duration>0) duration=2;
//new(数值越小越快,最小值1) #必须存在前缀if,否则卡死
this._movementDuration = duration;
if (duration === 0) {
this._offsetX = x;
this._offsetY = y;
}
}
};

谢谢大佬