JS让代码中间间隔一段时间后执行

console.log("我执行了");
sleep(3000);
console.log("我3000ms后执行了");

function sleep(numberMillis) {
    var now = new Date();
    var exitTime = now.getTime() + numberMillis;
    while (true) {
        now = new Date();
        if (now.getTime() > exitTime)
            return;
    }
}