完美运动框架封装函数startMove

function getStyle(obj, attr)
{
if(obj.currentStyle)
{
return obj.currentStyle[attr];//ie
}
else
{
return getComputedStyle(obj, false)[attr];//ff
}
}

function startMove(obj, json, fn)
{
clearInterval(obj.timer);//开定时器之前先关掉原有的计时器
obj.timer=setInterval(function (){
var bStop=true; //这一次运动就结束了――所有的值都到达了
for(var attr in json)
{
//1.取当前的值
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])
{
bStop=false;
}

if(attr=='opacity')
{
obj.style.filter='alpha(opacity:'+(iCur+iSpeed)+')';
obj.style.opacity=(iCur+iSpeed)/100;
}
else
{
obj.style[attr]=iCur+iSpeed+'px';
}
}

if(bStop)
{
clearInterval(obj.timer);

if(fn)
{
fn();
}
}
}, 30)
}