javascript 运动框架

function getStyle(obj,attr)
 {
    if(obj.currentStyle)
    {
         return obj.currentStyle[attr];
    }
    else
    {
         //return obj.getComputedStyle(obj,false).getPropertyValue([attr]);
         return document.defaultView.getComputedStyle(obj,false)[attr];
    }
 
 }
function startMove(obj, json,fn)
{

  
     clearInterval(obj.timer);
     obj.timer=setInterval(function(){
     
       for(var attr in json)
       {
           //1取当前值
           var iCur=0;
           if(attr=='opacity')
           { 
               iCur=parseInt(parseFloat(getStyle(obj,attr))*100);
           
           }else
           {
               iCur=parseInt(getStyle(obj,attr));
           }
           //2算速度
           var iSpeed=(json[attr]-iCur)/8;
           iSpeed=iSpeed>0?Math.ceil(iSpeed):Math.floor(iSpeed);
             //3检测停止
           if(iCur==json[attr])
           {
                var flg=false;
                for(var attr in json)
                   {
                      if(attr=='opacity')
                      {
                          if(json[attr]==parseInt(parseFloat(getStyle(obj,attr))*100))
                          {
                               flg=true;
                          }else
                          {
                               flg=false;
                               break;
                          }
                      }else
                      {  
                          if(json[attr]==parseInt(getStyle(obj,attr)))
                          {
                               flg=true;
                          }else
                          {
                               flg=false;
                               break;
                          }
                       }
                   }
                   //当所有运动都全部完成时关闭定时器
                  if(flg)
                  {
                       clearInterval(obj.timer);
                  }
                //是否链式运动          
               if(fn)
               {
                  fn();
               }
           }else
           {
                if(attr=='opacity')
               { 
                  obj.style.filter='alpha(opacity:'+(iCur+iSpeed)+')';
                  obj.style.opacity=(iCur+iSpeed)/100;
               }else
               {
                   obj.style[attr]=iCur+iSpeed+"px";
               }
               
           }
       }
      
     
     },30); 

}