纯JS实现页码切换飞页动画效果

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>www.jb51.net JS飞入效果</title>
  <link rel="stylesheet" href="stylesheets/base.css" rel="external nofollow" >
  <style>
    body{
      background:#000;
    }
    .header{
      width: 100%;
      height: 40px;
      background:#fff;
      font:bold 30px/40px '微软雅黑';
      text-align:center;
    }
    input{
      background:#fff;
      margin-top:5px;
      width: 50px;
      height: 20px;
      font:bold 12px/20px '微软雅黑';
    }
    ul{
      width: 360px;
      height: 360px;
      margin:50px auto;
    }
    ul li{
      width: 100px;
      height: 100px;
      background:skyblue;
      float:left;
      margin:5px;
    }
  </style>
  <script src="move.js"></script>
  <script>
    window.onload=function(){
      var oBtn=document.getElementById('btn1');
      var oUl=document.getElementsByTagName('ul')[0];
      var aLi=oUl.children;
      //用数组来存放没个li的位置
      var arr=[];
      //存位置
      for(var i=0;i<aLi.length;i++) {
        arr[i] = {
        left:aLi[i].offsetLeft,
        top:aLi[i].offsetTop
        };
      }
      //给目前的li定位
      for(var i=0;i<arr.length;i++){
        aLi[i].style.position='absolute';
        aLi[i].style.left=arr[i].left+'px';
        aLi[i].style.top=arr[i].top+'px';
        aLi[i].style.margin=0;
      }
      //当点击的时候开定时器，让li一个一个的走
      var iNow=0;
      var timer=null;
      var bReady=false;
      oBtn.onclick=function(){
        if(bReady){return;}
        bReady=true;
        timer=setInterval(function(){
          move(aLi[iNow],{left:0,top:0,height:0,width:0,opacity:0},{'duration':200,'complete':function(){
            if(iNow==arr.length-1){
              clearInterval(timer);
              back();
              bReady=false;
            }
            iNow++;
          }});
        },220);
      };
      function back(){
        timer=setInterval(function(){
          iNow--;
          move(aLi[iNow],{left:arr[iNow].left,top:arr[iNow].top,height:100,width:100,opacity:1},{'duration':200,'complete':function(){
            if(iNow==0){
              clearInterval(timer);
            }
          }});
        },220);
      }
    };
  </script>
</head>
<body>
  <div class="header">飞页效果</div>
  <input type="button" value="走你" id="btn1">
  <ul>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
    <li></li>
  </ul>
</body>
</html>

/**
 * Created by Jason on 2016/11/7.
 */
function getStyle(obj,sName){
  return (obj.currentStyle || getComputedStyle(obj,false))[sName];
}
function move(obj,json,options){
  var options=options || {};
  var duration=options.duration || 1000;
  var easing=options.easing || 'linear';
  var start={};
  var dis={};
  for(name in json){
    start[name]=parseFloat(getStyle(obj,name));
    dis[name]=json[name]-start[name];
  }
  //start {width:50,} dis {width:150}
  //console.log(start,dis);
  var count=Math.floor(duration/30);
  var n=0;
  clearInterval(obj.timer);
  obj.timer=setInterval(function(){
    n++;
    for(name in json){
      switch (easing){
        case 'linear':
          var a=n/count;
          var cur=start[name]+dis[name]*a;
          break;
        case 'ease-in':
          var a=n/count;
          var cur=start[name]+dis[name]*a*a*a;
          break;
        case 'ease-out':
          var a=1-n/count;
          var cur=start[name]+dis[name]*(1-a*a*a);
          break;
      }
      if(name=='opacity'){
        obj.style.opacity=cur;
      }else{
        obj.style[name]=cur+'px';
      }
    }
    if(n==count){
      clearInterval(obj.timer);
      options.complete && options.complete();
    }
  },30);
}