原生jsシームレスな輪播プラグインの使用について

<div class="sliders-wraper" id="rotation-1">
 <ul class="sliders clear">
 <li class="slider" style="background:purple">5</li>
 <li class="slider" style="background:pink">1</li>
 <li class="slider" style="background:beige">2</li>
 <li class="slider" style="background:gold">3</li>
 <li class="slider" style="background:skyblue">4</li>
 <li class="slider" style="background:purple">5</li>
 <li class="slider" style="background:pink">1</li>
 </ul>
 <div class="pagenation">
 <div class="page page-active"><a></a></div>
 <div class="page"><a></a></div>
 <div class="page"><a></a></div>
 <div class="page"><a></a></div>
 <div class="page"><a></a></div>
 </div>
 <span class='prev rotation-btn'><</span>
 <span class='next rotation-btn'>></span>
</div>

*{margin: 0;padding: 0;box-sizing: border-box;}
.clear{zoom: 0;}
.clear:after{content: '';display: block;overflow: hidden;clear: both;widows: 0;height: 0;}
.sliders-wraper{width: 100%;height: 400px;line-height: 400px;
 overflow: hidden;position: relative;text-align: center;}
.sliders{position: absolute;list-style: none;font-size: 50px;}
.slider{float: left;}
.rotation-btn{position: absolute;top: 50%;width: 50px;height: 50px;
 line-height: 50px;margin-top: -25px;font-size: 30px;color: #ccc;cursor: pointer;}
.prev{left:0;}
.next{right:0;}
.pagenation{position: absolute;bottom: 10px;width: 100%;height: 25px;line-height: 25px;}
.pagenation .page{width: 40px;height: 25px;display: inline-block;cursor: pointer;}
.pagenation .page a{display: block;width: 30px;height: 5px;border: 1px solid #ccc;
 border-radius: 5px;background: transparent;margin: 10px auto;}
.pagenation .page-active a{border-color: #0076ff;background-color: #0076ff;}

;(function(doc, win){
 function Rotation(obj){
 this.wraper = doc.getElementById(obj.el) //  
 this.sliders = this.wraper.getElementsByClassName('sliders')[0] //     
 this.slideList = this.sliders.getElementsByClassName('slider') //    
 this.length = this.slideList.length
 this.index = 1 //          
 this.timer = null //         
 this.animation = null //       

 //  obj         
 this.mode = 'easy-in-out'//    ，   'linear'
 this.step = 5 //        
 this.delay = 2500 //    
 this.duration = 40 //        
 this.auto = true //        
 this.btn = false //       
 this.focusBtn = true //        

 for(var k in obj)
 this[k] = obj[k]
 if(this.btn){
 this.prev = this.wraper.getElementsByClassName('prev')[0]
 this.next = this.wraper.getElementsByClassName('next')[0]
 }
 if(this.focusBtn){
 this.pagenation = this.wraper.getElementsByClassName('pagenation')[0]
 this.pageList = this.pagenation.getElementsByClassName('page')
 this.activePage = 0 //        
 }
 this.init()
 }

 var D = Rotation.prototype
 /*
 * func init
 *      
 * @para 0 
 */
 D.init = function(){
 this.width = this.wraper.clientWidth
 if(this.mode == 'linear')
 this.duration = 1
 for(var i=0; i<this.length; i++)
 this.slideList[i].style.width = this.width + 'px'

 this.sliders.style.width = this.width * this.length + 'px'
 this.sliders.style.marginLeft = -this.width + "px";
 this.handler()
 this.auto && this.autoPlay()
 }

 D.getStyle = function(obj, attr){
 return obj.currentStyle?obj.currentStyle[attr]:getComputedStyle(obj, false)[attr]; 
 }
 /*
 * @method bind
 *       
 * bind events 
 */
 D.handler = function(){
 var _th = this,i=0
 if(this.btn){
 this.prev.onclick = function(){
 _th.turnLeft();
 }
 this.next.onclick = function(){
 _th.turnRight();
 }
 }
 if(this.focusBtn){
 for(; i<this.pageList.length; i++){
 this.pageList[i].key = i
 this.pageList[i].function(){
  _th.index = this.key + 1
  _th.toggleClass()
 }
 }
 }
 this.wraper.onmouseover = function(){
 clearInterval(_th.animation);
 }
 this.wraper.onmouseout = function(){
 _th.auto && _th.autoPlay()
 }
 }
 /*
 * func turnRight
 *       
 * @para 0
 */
 D.turnRight = function(){
 this.index++;
 if(this.index == this.length-1){
 this.index=1;
 this.sliders.style.marginLeft = 0;
 }
 this.toggleClass(); 
 }
 /*
 * func turnLeft
 *       
 * @para 0
 */
 D.turnLeft = function(){
 this.index--;
 if(this.index == 0){
 this.index = this.length-2;
 this.sliders.style.marginLeft = -this.width * (this.length-1) + "px";
 }
 this.toggleClass();
 }
 /*
 * func toggleClass
 *         ,          
 * @para 0
 */
 D.toggleClass = function(){
 if(this.focusBtn){
 this.pageList[this.activePage].className = "page";
 this.pageList[this.index-1].className = "page page-active";
 this.activePage = this.index-1;
 }
 this.slide(-this.index * this.width);
 }
 /*
 * func slide
 *       ，    
 * @param ins     
 */
 D.slide = function(ins){
 var _th = this
 //              
 if(_th.timer) clearInterval(_th.timer);

 _th.timer = setInterval(move,_th.duration);

 function move(){

 var currentPosition = parseFloat(_th.sliders.style.marginLeft);
 //                       
 var n = ins-currentPosition<0?-1:1;

 if(Math.abs(ins-currentPosition) < _th.step){
 _th.sliders.style.marginLeft = ins + "px";
 clearInterval(_th.timer);
 }else{
 //       ，        
 if(_th.mode == 'easy-in-out')
  _th.step = Math.abs(ins-currentPosition)/5
 _th.sliders.style.marginLeft = currentPosition + n*_th.step + "px";
 }
 
 }
 }
 /*
 * func autoPlay
 *       
 * @para 0
 */
 D.autoPlay = function(){
 var _th = this
 clearInterval(_th.animation)
 _th.animation = setInterval(function(){
 _th.turnRight();
 },_th.delay)
 }
 /*
 * func debounce
 *     
 * @para fn<      > delay<    >
 * @value func
 */
 D.debounce = function(fn,delay){
 var timer = null
 return function(){
 if(timer){
 clearTimeout(timer)
 }
 timer = setTimeout(fn,delay)
 }
 }
 /*
 * func refresh
 *       ，                        
 * @para 0
 */
 D.refresh = function(){
 var _th = this
 this.debounce(function(){
 _th.init()
 _th.toggleClass()
 },100)()
 }
 /*
 * func rotation
 *      
 * @para obj         
 * @value       
 */
 win.rotation = function(obj){
 return new Rotation(obj)
 }
})(document, window)

var r2 = rotation({
 el: 'rotation-1',
 mode: 'easy-in-out', //    
 auto: true,//      
 btn: true, //    
 focusBtn: false//  
})
window.onresize = function(){
 r2 && r2.refresh()
}