在setTimeout中调用多个函数 [英] Calling more than 1 function in setTimeout

问题描述

我想在JavaScript中的一个setTimeout()的末尾调用两个函数. 是否可以，如果是"，将首先执行哪个?

setTimeout(function() {
    playmp3(nextpage);
    $.mobile.changePage($('#' + nextpage));
}, playTime);

解决方案

有可能吗?

是的，为什么不呢? setTimeout使用回调 function 作为它的第一个参数.它是一个回调函数，这一事实不会改变任何东西.遵循通常的规则.

哪个首先执行?

除非您使用的是基于Promise或基于回调的代码，否则Javascript会顺序运行 ，因此将按照编写它们的顺序调用函数.

setTimeout(function() {
  function1() // runs first
  function2() // runs second
}, 1000)

但是，如果您这样做:

setTimeout(function() {
  // after 1000ms, call the `setTimeout` callback
  // In the meantime, continue executing code below
  setTimeout(function() {
    function1() //runs second after 1100ms
  },100)

  function2() //runs first, after 1000ms
},1000)

然后顺序更改，因为setTimeout是 async ，在这种情况下，它会在计时器到期后被触发./p>

---

如果您的上述代码有问题，那么您的任何一个函数都将包含 async 代码(setInterval()，setTimeout()，DOM事件，WebWorker代码等)，这会使您感到困惑.

• async 在这里代表 asynchronous ，这意味着它不是按特定顺序发生的

I want to call two functions at the end of one setTimeout() in JavaScript. Is it possible and if "yes" which one will be executed first?

setTimeout(function() {
    playmp3(nextpage);
    $.mobile.changePage($('#' + nextpage));
}, playTime);

解决方案

Is it possible?

Yes, why wouldn't it be? setTimeout takes a callback function as it's 1st argument. The fact that it's a callback function doesn't change anything; the usual rules apply.

which one will be executed first?

Unless you're using Promise-based or callback-based code, Javascript runs sequentially so your functions would be called in the order you write them down.

setTimeout(function() {
  function1() // runs first
  function2() // runs second
}, 1000)

However, if you do this:

setTimeout(function() {
  // after 1000ms, call the `setTimeout` callback
  // In the meantime, continue executing code below
  setTimeout(function() {
    function1() //runs second after 1100ms
  },100)

  function2() //runs first, after 1000ms
},1000)

then the order changes since setTimeout is async in which case it get's fired after it's timer expires (JS continued and executed function2() in the meantime)

---

If you have issues with your above code then either one of your functions contains async code (setInterval(),setTimeout(), DOM event, WebWorker code etc), which confuses you.

• async here stands for asynchronous meaning not occurring in a particular order

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