带回调函数的js运动框架

function startMove(obj, json, endFun) {

    //开始前关闭之前obj上的定时器

    clearInterval(obj.timer);

    //定时器

    obj.timer = setInterval(function() {

        var bStop = true; //假设所有值都到目标

        for(var attr in json) {//循环json数组

            //单独处理透明度

            if(attr == 'opacity') {

                var cur = Math.round(parseFloat(getStyle(obj, attr)) * 100);

            } else {

                var cur = parseInt(getStyle(obj, attr));

            }

            //速度处理

            var speed = (json[attr] - cur) / 6;

            speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);

            //如果当前的没到目标值

            if(cur != json[attr])

                bStop = false;

            //运动

            if(attr == 'opacity') {

                obj.style.opacity = (cur + speed) / 100;

                obj.style.filter = 'alpha(opacity:' + (cur + speed) + ')';

            } else {

                obj.style[attr] = cur + speed + 'px';

            }

        }

        //所有的都到达目标值

        if(bStop) {

            clearInterval(obj.timer);

            if(endFun) endFun();

        }

    }, 30);  }