原生JS运动实现轮播图

//多物体多值运动+回调机制
function startMove(dom, attrObj, callback) {
 var key = true;
 var iSpeed = null,
  iCur = null;
 clearInterval(dom.timer);
 if (key) {
  dom.timer = setInterval(function() {
  //bStop用来判断是否开始执行回调函数
   var bStop = true;
   //判断传入目标值中的“键”类型是否为opacity
   for (var attr in attrObj) {
   //若要改变的样式为opacity，则将元素的opacity扩大100被进行操作
    if (attr === 'opacity') {
     iCur = parseFloat(getStyle(dom, attr)) * 100;
    } else {
     iCur = parseInt(getStyle(dom, attr));
    }
    //运动速度设为目标值减去当前值的一半，即当前状态离目标值越接近，运动速度越小
    iSpeed = (attrObj[attr] - iCur) / 2;
    //对速度进行取整
    iSpeed = iSpeed > 0 &＃63; Math.ceil(iSpeed) : Math.floor(iSpeed);
    if (attr === 'opacity') {
     dom.style.opacity = (iCur + iSpeed) / 100;
    } else {
     dom.style[attr] = iCur + iSpeed + 'px';
    }
    if (iCur !== attrObj[attr]) {
     bStop = false;
    }
   }
   //当bStop为true时，元素的所有样式均已达到目标值，清理定时器并执行回调函数
   if (bStop) {
    clearInterval(dom.timer);
    typeof callback == 'function' && callback();
   }
  }, 30)
 }
 if (!key) {

 }
}
//用来获取元素实时的样式值
function getStyle(elem, prop){
 if (window.getComputedStyle){
  return window.getComputedStyle(elem, null)[prop];
 }
}

 

  

   
  
  

   
  
  

   
  
  

   
  
  

   
  
 
 
<
 
>
 

  
  
  
  
 

var timer = null;
var sliderPage = document.getElementsByTagName('ul')[0];
var moveWidth = sliderPage.children[0].offsetWidth;
var num = sliderPage.children.length - 1;
var leftBtn = document.getElementsByClassName('leftBtn')[0];
var rightBtn = document.getElementsByClassName('rightBtn')[0];
var lock = true;
var index = 0;
var indexArray = document.getElementsByClassName('sliderIndex')[0].getElementsByTagName('span');
//索引切换
for (var i = 0; i left');
}
//向右翻
rightBtn.Onclick= function (){
 autoMove('left->right');
}
//direction
//默认轮播方向 'left->right' / undefined
//点击left按钮 'right->left'
function autoMove(direction){
 clearTimeout(timer);
 if (lock){
  lock = false;

  if (!direction || direction === 'left->right'){
   index++;
   startMove(sliderPage, {left: sliderPage.offsetLeft - moveWidth}, function(){
    if (sliderPage.offsetLeft === - num * moveWidth){
     index = 0;
     sliderPage.style.left = '0px';
    }
    timer = setTimeout(autoMove, 3000);
    lock = true;
    changeIndex(index);
   });
  }else if(direction === 'right->left'){
   if (sliderPage.offsetLeft === 0){
    index = num;
    sliderPage.style.left = - num * moveWidth + 'px';
   }
   index--;
   startMove(sliderPage, {left: sliderPage.offsetLeft + moveWidth}, function () {
    timer = setTimeout(autoMove, 3000);
    lock = true;
    changeIndex(index);
   })
  }
 }
}