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);
}