js执行机制(1)

   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');