和上一个差别不大

Animation.prototype.changeSrc = function (el,imgList) {

var me = this;

var len = imgList.length;

var taskFn;

var type;

if (len) {

taskFn = function (next, time) {

var index = Math.min(time / me.interval | 0 , len-1);

el.src = imageList[index]

//结束时跳到下一个

if (index === len - 1) {

next();

}

}

type = TASK_ASYNC;

} else {

//这里的next就是全局方法 next

taskFn = next;

type = TASK_SYNC;

}

return this._add(taskFn,type)

}