在 setTimeout 中调用 1 个以上的函数

Question

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);

Answer 1

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

Answer 2

I've used this syntax and it works fine:

$('#element').on('keypress change', function (e) {
   setTimeout(function () { function1(); function2(); }, 500, $(this));
});

Answer 3

5This worked like a charm for me (it's multiple functions that fire after an element is clicked):

const elem = document.getElementById("element-id");
    function parent(){
         elem.addEventListner("click", func1);
              function func1(){
                   // code here
                 setTimeout(func2, 250) //func2 fires after 200 ms
                  }
              function func2(){
                   // code here
                 setTimeout(func3, 100) //func3 fires 100 ms after func2 and 350 ms after func1
                  }
               function func3(){
                   // code here
                  }
    }
    parent():