运动框架

运动框架演变过程
startMove(iTarget) 运动框架
startMove(obj, iTarget) 多物体
startMove(obj, attr, iTarget) 任意值
startMove(obj, attr, iTarget, fn) 链式运动
startMove(obj, json) 多值运动
startMove(obj, json, fn) 完美运动框架

完美运动框架：

function startMove(obj, attr, iTarget, fnEnd)
{
    clearInterval(obj.timer);
    obj.timer=setInterval(function (){
        var cur=0;
        
        if(attr=='opacity')
        {
            cur=Math.round(parseFloat(getStyle(obj, attr))*100);
        }
        else
        {
            cur=parseInt(getStyle(obj, attr));
        }
        
        var speed=(iTarget-cur)/6;
        speed=speed>0?Math.ceil(speed):Math.floor(speed);
        
        if(cur==iTarget)
        {
            clearInterval(obj.timer);
            
            if(fnEnd)fnEnd();
        }
        else
        {
            if(attr=='opacity')
            {
                obj.style.filter='alpha(opacity:'+(cur+speed)+')';
                obj.style.opacity=(cur+speed)/100;
            }
            else
            {
                obj.style[attr]=cur+speed+'px';
            }
        }
    }, 30);
}