JavaScript运动框架

function getStyle(obj, attr) {
    return obj.currentStyle ? obj.currentStyle[attr] : getComputedStyle(obj, false)[attr];
}

function startMove(obj, json, fn) {
    clearInterval(obj.timer);
    obj.timer = setInterval(function() {
        var bStop = true; //这一次运动结束——————所有值都到达了

        for(var attr in json) {

            //1.取当前的值
            var iCur = 0;
            if(attr == 'opacity') {
                var iCur = parseInt(parseFloat(getStyle(obj, attr)) * 100);
            }
            else {
                var iCur = parseInt(getStyle(obj, attr));
            }

            //2.计算速度
            var iSpeed = (json[attr] - iCur)/6;
            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);
}