代码是否包含在函数中？

function test() {
    setTimeout(...);     

    // code that you cannot modify?
}

在这种情况下，您可以阻止该函数进一步执行，然后再次运行它：

function test(flag) {

    if(!flag) {

        setTimeout(function() {

           alert();
           test(true);

        }, 5000);

        return;

    }

    // code that you cannot modify

}

上周我遇到了需要类似功能的情况，这让我想到了这篇文章。基本上我认为@AndreKR 所指的“忙等待”在很多情况下都是合适的解决方案。下面是我用来占用浏览器并强制等待条件的代码。

function pause(milliseconds) {
	var dt = new Date();
	while ((new Date()) - dt <= milliseconds) { /* Do nothing */ }
}

document.write("first statement");
alert("first statement");

pause(3000);

document.write("<br />3 seconds");
alert("paused for 3 seconds");

请记住，此代码实际上会阻止您的浏览器。希望它可以帮助任何人。

使用 ES6 & promises & async 你可以实现同步运行。

那么代码在做什么呢？

 1. Calls setTimeOut 1st inside of demo then put it into the webApi Stack
 2. Creates a promise from the sleep function using the setTimeout, then resolves after the timeout has been completed;
 3. By then, the first setTimeout will reach its timer and execute from webApi stack. 
 4. Then following, the remaining alert will show up.


function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

async function demo() {
  setTimeout("alert('this alert is timedout and should be the first');", 5000);
  await sleep(5000);
  alert('this should be the second one');
}
demo();

只需将它放在回调中：

setTimeout(function() {
    alert('this alert is timedout and should be the first');
    alert('this should be the second one');
}, 5000);

不，由于 Javascript 中没有延迟功能，因此除了忙等待（这会锁定浏览器）之外，没有其他方法可以做到这一点。