无限循环轮播图之运动框架(原生JS实现)

function getStyle(obj,name){
 if(obj.currentStyle){
 return obj.currentStyle[name];
 }else{
 return getComputedStyle(obj,false)[name];
 }
}
function move(obj,json,options){
 var options=options || {};
 var duration=options.duration || 800;
 var easing=options.easing || 'linear';
 var n=0;
 var start={};
 var dis={};
 var count=Math.ceil(duration/30);
 //{top:0,left:0}
 for(name in json){
 start[name]=parseFloat(getStyle(obj,name));
 dis[name]=json[name]-start[name];
 }

 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-out':
 var a=1-n/count;
 var cur=start[name]+dis[name]*(1-a*a*a);
 break;
 case 'ease-in':
 var a=n/count;
 var cur=start[name]+dis[name]*a*a*a;
 break;
 }
 if(name=='opacity'){
 obj.style[name]=cur;
 }else{
 obj.style[name]=cur+'px';
 }
 }
 if(n==count){
 clearInterval(obj.timer);
 options.complete && options.complete();
 }
 },30);
}