练习运动

function getStyle(obj, name) {
    if (obj.currentStyle) {
        return obj.currentStyle[name];
    } else {
        return getComputedStyle(obj, false)[name];
    }
}

function move(obj,json,options) {
    clearInterval(obj.timer);
    options=options||{};
    options.time=options.time||1000;
    options.easing=options.easing||'linear';
    var start = {};
    var dis = {};
    for(var name in json){
        start[name] = parseFloat(getStyle(obj, name));
        dis[name] = json[name] - start[name];
    }
    var count = Math.floor(options.time / 30);
    var n = 0;
    obj.timer = setInterval(function () {
        n++;
        for(var name in json){
            switch(options.easing){
                case 'linear':
                    var a= n/count;
                    var cur=start[name]+dis[name]*a;
                    break;
                case 'ease-in':
                    var a=n/count;
                    var cur=start[name]+dis[name]*a*a*a*a*a;
                    break;
                case 'ease-out':
                    var a=1-n/count;
                    var cur=start[name]+dis[name]*(1-a*a*a*a*a);
                    break;
            }

            if (name == 'opacity') {
                obj.style.opacity = cur;
                obj.style.filter = 'alpha(opacity:' + cur * 100 + ')';
            } else {
                obj.style[name] = cur + 'px';
            }
        }
        if (n == count) {
            clearInterval(obj.timer);
             options.fn && options.fn();
    }
    }, 30);
}