有没有比下面的pausecomp函数(取自此处)更好的方法来设计JavaScript中的睡眠?

function pausecomp(millis)
{
    var date = new Date();
    var curDate = null;
    do { curDate = new Date(); }
    while(curDate-date < millis);
}

这不是JavaScript中的Sleep的重复-动作之间的延迟;我希望在函数的中间有一个真正的睡眠,而不是在代码执行之前有一段延迟。


当前回答

我在JavaScript sleep/wait上搜索了很多网页。。。如果你想让JavaScript“RUN,DELAY,RUN”。。。大多数人得到的要么是“RUN,RUN(无用的东西),RUN”,要么是“RUN,RUN+延迟RUN”。。。

我想:这是一个有效的解决方案。。。但你必须把你的跑步代码切碎…:是的,我知道,这只是一个更容易理解的重构。。。还

示例1:

<html>
<body>
<div id="id1">DISPLAY</div>

<script>
// JavaScript sleep by "therealdealsince1982"; copyrighted 2009
// setInterval
var i = 0;

function run() {
    // Pieces of codes to run
    if (i == 0){document.getElementById("id1").innerHTML= "<p>code segment " + i + " is ran</p>"; }
    if (i == 1){document.getElementById("id1").innerHTML= "<p>code segment " + i + " is ran</p>"; }
    if (i == 2){document.getElementById("id1").innerHTML= "<p>code segment " + i + " is ran</p>"; }
    if (i >2){document.getElementById("id1").innerHTML= "<p>code segment " + i + " is ran</p>"; }
    if (i == 5){document.getElementById("id1").innerHTML= "<p>all code segment finished running</p>"; clearInterval(t); } // End interval, stops run
    i++; // Segment of code finished running, next...
}

run();
t = setInterval("run()", 1000);

</script>
</body>
</html>

示例2:

<html>
<body>
<div id="id1">DISPLAY</div>

<script>
// JavaScript sleep by "therealdealsince1982"; copyrighted 2009
// setTimeout
var i = 0;

function run() {
    // Pieces of codes to run, can use switch statement
    if (i == 0){document.getElementById("id1").innerHTML= "<p>code segment " + i + " ran</p>"; sleep(1000);}
    if (i == 1){document.getElementById("id1").innerHTML= "<p>code segment " + i + " ran</p>"; sleep(2000);}
    if (i == 2){document.getElementById("id1").innerHTML= "<p>code segment " + i + " ran</p>"; sleep(3000);}
    if (i == 3){document.getElementById("id1").innerHTML= "<p>code segment " + i + " ran</p>";} //stops automatically
    i++;
}

function sleep(dur) {t=setTimeout("run()", dur);} // Starts flow control again after 'dur'

run(); // Starts
</script>
</body>
</html>

示例3:

<html>
<body>
<div id="id1">DISPLAY</div>

<script>
// JavaScript sleep by "therealdealsince1982"; copyrighted 2009
// setTimeout
var i = 0;

function flow() {
    run(i);
    i++; // Code segment finished running, increment i; can put elsewhere
    sleep(1000);
    if (i == 5) {clearTimeout(t);} // Stops flow, must be after sleep()
}

function run(segment) {
    // Pieces of codes to run, can use switch statement
    if (segment == 0){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment == 1){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment == 2){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment >2){document.getElementById("id1").innerHTML= "<p>code segment "+ segment +" is ran</p>"; }
}

function sleep(dur) {t=setTimeout("flow()", dur);} // Starts flow control again after 'dur'

flow(); // Starts flow
</script>
</body>
</html>

示例4:

<html>
<body>
<div id="id1">DISPLAY</div>

<script>
// JavaScript sleep by "therealdealsince1982"; copyrighted 2009
// setTimeout, switch
var i = 0;

function flow() {
    switch(i)
    {
        case 0:
            run(i);
            sleep(1000);
            break;
        case 1:
            run(i);
            sleep(2000);
            break;
        case 5:
            run(i);
            clearTimeout(t); // Stops flow
            break;
        default:
            run(i);
            sleep(3000);
            break;
    }
}

function run(segment) {
    // Pieces of codes to run, can use switch statement
    if (segment == 0){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment == 1){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment == 2){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    if (segment >2){document.getElementById("id1").innerHTML= "<p>code segment " + segment + " is ran</p>"; }
    i++; // Current segment of code finished running, next...
}

function sleep(dur) {t=setTimeout("flow()", dur);} // Starts flow control again after 'dur'

flow(); // Starts flow control for first time...
</script>
</body>
</html>

其他回答

require('deasync').sleep(100);

可以使用带有递增较大值的闭包调用setTimeout()。

var items = ['item1', 'item2', 'item3'];

function functionToExecute(item) {
  console.log('function executed for item: ' + item);
}

$.each(items, function (index, item) {
  var timeoutValue = index * 2000;
  setTimeout(function() {
    console.log('waited ' + timeoutValue + ' milliseconds');
    functionToExecute(item);
  }, timeoutValue);
});

结果:

waited 0 milliseconds
function executed for item: item1
waited 2000 milliseconds
function executed for item: item2
waited 4000 milliseconds
function executed for item: item3

出于对$DEITY的热爱,请不要使用忙等待睡眠功能。setTimeout和setInterval可以满足您的需要。

var showHide=document.getElementById('showHide');setInterval(()=>{showHide.style.visibility=“初始”;setTimeout(()=>{showHide.style.visibility=“隐藏”}, 1000);}, 2000); <div id=“showHide”>您好!再见</分区>

每隔两秒隐藏文本一秒。这显示了如何使用setInterval和setTimeout每秒显示和隐藏文本。

如果您使用的是Node.js,您可以看看fiber——一种对节点的原生C扩展,一种多线程模拟。

它允许您以阻塞光纤中的执行的方式进行真正的睡眠,但在主线程和其他光纤中是非阻塞的。

下面是他们自己自述文件中的一个例子:

// sleep.js

var Fiber = require('fibers');

function sleep(ms) {
    var fiber = Fiber.current;
    setTimeout(function() {
        fiber.run();
    }, ms);
    Fiber.yield();
}

Fiber(function() {
    console.log('wait... ' + new Date);
    sleep(1000);
    console.log('ok... ' + new Date);
}).run();
console.log('back in main');

–结果如下:

$ node sleep.js
wait... Fri Jan 21 2011 22:42:04 GMT+0900 (JST)
back in main
ok... Fri Jan 21 2011 22:42:05 GMT+0900 (JST)

这可以使用Java的睡眠方法来完成。我已经在Firefox和Internet Explorer中测试过它,它不会锁定计算机,不会占用资源,也不会导致无休止的服务器攻击。对我来说,这似乎是一个干净的解决方案。

首先,您必须在页面上加载Java并使其方法可用。为了做到这一点,我这样做了:

<html>
<head>

<script type="text/javascript">

  function load() {
    var appletRef = document.getElementById("app");
    window.java = appletRef.Packages.java;
  } // endfunction

</script>

<body onLoad="load()">

<embed id="app" code="java.applet.Applet" type="application/x-java-applet" MAYSCRIPT="true" width="0" height="0" />

然后,当您想要在JavaScript代码中轻松暂停时,您需要做的就是:

java.lang.Thread.sleep(xxx)

其中xxx是以毫秒为单位的时间。在我的案例中(作为理由),这是一家非常小的公司后端订单履行的一部分,我需要打印一张必须从服务器加载的发票。我是通过将发票(作为网页)加载到iFrame中,然后打印iFrame来完成的。

当然,我必须等到页面完全加载后才能打印,所以JavaScript代码必须暂停。我通过让发票页面(在iFrame中)使用onLoad事件更改父页面上的隐藏表单字段来实现这一点。打印发票的父页面上的代码如下(为清晰起见,将不相关的部分切割):

var isReady = eval('document.batchForm.ready');
isReady.value = 0;

frames['rpc_frame'].location.href = url;

while (isReady.value == 0) {
  java.lang.Thread.sleep(250);
} // endwhile

window.frames['rpc_frame'].focus();
window.frames['rpc_frame'].print();

因此,用户按下按钮,脚本加载发票页面,等待,每季度检查一次发票页面是否完成加载,并弹出打印对话框,供用户将其发送到打印机。QED。