function getStyle(obj,attr){
if(obj.currentStyle){
return obj.currentStyle[attr];
}
else{
return getComputedStyle(obj,false)[attr];
}
}
function starMove(obj,json,fn){
var flag = true;
for(var attr in json){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
//1.取当前值
var iCur = 0;
if(attr == 'opacity'){
iCur = Math.round(parseInt(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]){
flag = false;
}
else{
if(attr == 'opacity'){
obj.style.filter = 'alpha:(opacity:'+(iCur+iSpeed)+')';
obj.style.opacity = (iCur+iSpeed) /100;
}
else{
obj.style[attr] = iCur+iSpeed+'px';
}
}
if(flag){
clearInterval(obj.timer);
if(fn){
fn();
}
}
}
},30)
}