js实现无缝滚动双图切换效果

<div class="wrap">
 <ul class="list">
  <li>
   <img src="img/img0.png">
  </li>
   <li>
   <img src="img/img1.png">
  </li>
 </ul>
 <a href="javascript:;" class="prev">prev</a>
 <a href="javascript:;" class="next">next</a>
</div>

(function(){
 var list=document.querySelector(".list");
 var imgs=document.querySelectorAll("img");
 var prev=document.querySelector(".prev");
 var next=document.querySelector(".next");
 var imgW=css(imgs[0],"width");//使用封装好的css()获取img的宽度
 var now=0;
 var imgData=["img/img0.png",
     "img/img1.png",
     "img/img2.png",
     "img/img3.png",];
 prev.onclick=function(){
  //找出接下来要显示的图片的下标
  var prev=(now-1+imgData.length)%imgData.length;
  //因为是从右往左运动，当前显示的应在右侧，即将显示的在左侧
  imgs[0].src=imgData[prev];
  imgs[1].src=imgData[now];
  //使用封装好的css()设置list的位置
  css(list,"left",-imgW);
  //使用封装好的运动函数来控制图片移动
  startMove(list,{left:0},2000,"easeOut");
  now=prev;
 }
 next.onclick=function(){
  var next=(now+1)%imgData.length;
  imgs[0].src=imgData[now];
  imgs[1].src=imgData[next];
  css(list,"left",0);
  startMove(list,{left:-imgW},2000,"easeOut");
  now=next;
 }
})();

var isMove=false;//记录定时器开关状态
prev.onclick=function(){
 if(isMove){
  return;
 }
 ....上述上一张操作js代码
 isMove=true;
 startMove(list,{left:-imgW},2000,"easeOut",function(){
  isMove=false; 
 });
}