js 监听 变量变化

var o = {};
setTimeout(function () {
    o.abb = '2';
}, 4000);
Object.defineProperties(o, {
    abb: {
        configurable: true,
        set: function (newValue) {
            var abb = newValue;
            console.log('你修改了 abb 的值：' + abb);
        }
    }
});