setTimeout(function () {

        console.log('执行定时任务');

    });

    new Promise(function (resolve) {

        console.log('马上执行for循环');

        for (var i = 0; i < 1000; i++) {

            i == 99 && resolve();

        }

    }).then(function () {

        console.log('执行then函数');

    })

    console.log('代码执行结束');