等待下一个功能不起作用

Question

我需要等待5秒钟才能运行第二行：

 function waitnext() { setTimeout('', 5000); alert('waited'); } 

但是，似乎在运行该功能时会立即打开警报。 任何想法如何解决这个问题？ 谢谢

Answer 1

 function waitnext() { setTimeout( function(){ alert('waited'); }, 5000); } waitnext(); 

您的语法错误。 在这里您可以找到文档https://www.w3schools.com/jsref/met_win_settimeout.asp

Answer 2

将您要运行的行经过一段时间延迟后作为setTimeout的回调

function waitnext() {
    setTimeout(function() {
        alert('waited'); // runs after 5000ms
    }, 5000);
}

Answer 3

在指定的毫秒数过去之后， setTimeout评估一个回调函数。

使用ES6的解决方案。

 let waitnext = () => { setTimeout(() => { // callback alert('waited'); }, 5000); } waitnext(); 

或使用ES5：

 'use strict'; var waitnext = function waitnext() { setTimeout(function () { // callback alert('waited'); }, 5000); }; waitnext(); 

Answer 4

function waitnext(){
 setTimeout(function(){
 alert('waited');
}, 5000);

尝试这个

Answer 5

一些样品...

 var myAlarm = e => console.log(e);
 var myStop = () => console.log('stop');
 var wait = (delay, callback) => setTimeout(callback, delay);

 wait(2000, () => myAlarm("finished after 2 seconds"));
 wait(3000, myStop);

 // the following line don´t work ...
 // the function was executed immediately
 wait(4000, myAlarm('cheesecake'));

//use setTimeout 
setTimeout(myStop, 1000);
// the following line don´t work ...
// the function was executed immediately
setTimeout(myAlarm('cheesecake'),3000);
// this works
setTimeout(() => myAlarm('cheesecake'),3000);