运动函数的封装

function startMove(obj,json,fn){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var flag = true;
for(var attr in json){
if(attr == "opacity"){
var iCur = parseInt(getStyle(obj,"opacity")*100);
}else{
var iCur = parseInt(getStyle(obj,attr));
}

var iTarget = json[attr];


var iSpeed = (iTarget - iCur)/8;
iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);


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

}


if(iCur != iTarget){

flag = false;
}

}

//所有的样式都达到目标值之后才能清除定时器

if(flag){
clearInterval(obj.timer);
if(fn){
fn();
}
}


},30);
}


function getStyle(obj,attr){
if(obj.currentStyle){
return obj.currentStyle[attr];
}
return getComputedStyle(obj,null)[attr];
}