blocks|key|1080441|text|您不能在浏览器Javascript中执行常规的ping操作，但您可以通过例如从远程服务器加载图像来确定远程服务器是否处于活动状态。如果加载失败，->服务器将关闭。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080442|您甚至可以使用onload-event来计算加载时间。下面是一个如何使用onload事件的example。|offset|length|1080443|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/3908414/js-verify-image-size/3908492#3908492^0|0|19|7|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

You can't do regular ping in browser Javascript, but you can find out if remote server is alive by for example loading an image from the remote server. If loading fails -> server down. 

You can even calculate the loading time by using onload-event. Here's an <a href="https://stackoverflow.com/questions/3908414/js-verify-image-size/3908492#3908492">example</a> how to use onload event.

blocks|key|865887|text|我不知道你运行的是哪个版本的Ruby，但是你有没有尝试过为ruby实现ping而不是javascript？http://raa.ruby-lang.org/project/net-ping/|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|865888|entityMap|0|LINK|mutability|MUTABLE|url|http://raa.ruby-lang.org/project/net-ping/^0|1H|16|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

I don't know what version of Ruby you're running, but have you tried implementing ping for ruby instead of javascript? <a href="http://raa.ruby-lang.org/project/net-ping/" rel="nofollow">http://raa.ruby-lang.org/project/net-ping/</a>

blocks|key|1080553|text|您可以尝试在您的web+page...something中使用PHP，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080554|<html><body>
<form+method="post"+name="pingform"+action="<?php+echo+$_SERVER['PHP_SELF'];+?>">
<h1>Host+to+ping:</h1>
<input+type="text"+name="tgt_host"+value='<?php+echo+$_POST['tgt_host'];+?>'> 
<input+type="submit"+name="submit"+value="Submit"+>
</form></body>
</html>
<?php

$tgt_host+=+$_POST['tgt_host'];
$output+=+shell_exec('ping+-c+10+'.+$tgt_host.');

echo+"<html><body+style=\"background-color:#0080c0\">
<script+type=\"text/javascript\"+language=\"javascript\">alert(\"Ping+Results:+"+.+$output+.+".\");</script>
</body></html>";

?>|code-block|syntax|javascript|1080555|这是没有测试的，所以它可能有拼写错误的etc...but，我相信它会工作。也可以改进。|1080556|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You could try using PHP in your web page...something like this:

<pre><code>&lt;html&gt;&lt;body&gt;
&lt;form method="post" name="pingform" action="&lt;?php echo $_SERVER['PHP_SELF']; ?&gt;"&gt;
&lt;h1&gt;Host to ping:&lt;/h1&gt;
&lt;input type="text" name="tgt_host" value='&lt;?php echo $_POST['tgt_host']; ?&gt;'&gt;&lt;br&gt;
&lt;input type="submit" name="submit" value="Submit" &gt;
&lt;/form&gt;&lt;/body&gt;
&lt;/html&gt;
&lt;?php

$tgt_host = $_POST['tgt_host'];
$output = shell_exec('ping -c 10 '. $tgt_host.');

echo "&lt;html&gt;&lt;body style=\"background-color:#0080c0\"&gt;
&lt;script type=\"text/javascript\" language=\"javascript\"&gt;alert(\"Ping Results: " . $output . ".\");&lt;/script&gt;
&lt;/body&gt;&lt;/html&gt;";

?&gt;
</code></pre>

This is not tested so it may have typos etc...but I am confident it would work. Could be improved too...

blocks|key|866012|text|为了保持您的请求快速，请缓存ping的服务器端结果，并每隔几分钟更新ping文件或数据库(或者按您希望的准确度更新)。你可以使用cron用你的8个ping命令运行一个shell命令，并将输出写入一个文件，view服务器会将这个文件包含到你的视图中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|866013|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

To keep your requests fast, cache the server side results of the ping and update the ping file or database every couple of minutes(or however accurate you want it to be). You can use cron to run a shell command with your 8 pings and write the output into a file, the webserver will include this file into your view.

blocks|key|1080707|text|标准ping的问题是它们是ICMP，这是a+lot+of+places+don't+let+through+for+security+and+traffic+reasons。这也许可以解释失败的原因。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1080708|Ruby1.9之前的版本有一个基于TCP的ping.rb，它将与Ruby+1.9%2B一起运行。您所要做的就是将其从1.8.7安装复制到其他地方。我只是通过pinging我的家庭路由器来确认它会运行。|style|CODE|1080709|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/Ping#History^0|K|1U|0|0|L|7|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@$A|U|B|V|F|G]]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]]|I|$J|$5|K|L|M|C|$N|O]]]]

The problem with standard pings is they're ICMP, which <a href="http://en.wikipedia.org/wiki/Ping#History">a lot of places don't let through for security and traffic reasons</a>. That might explain the failure. 

Ruby prior to 1.9 had a TCP-based <code>ping.rb</code>, which will run with Ruby 1.9+. All you have to do is copy it from the 1.8.7 installation to somewhere else. I just confirmed that it would run by pinging my home router.

blocks|key|1080752|text|这可能比这一切都容易得多。如果你想要加载你的页面，然后检查一些外部页面的可用性或内容来触发其他网页活动，你可以只使用javascript和php来完成，如下所示。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080753|yourpage.php|1080754|<?php
if+(isset($_GET['urlget'])){
++if+($_GET['urlget']!=''){
++++$foreignpage=+file_get_contents('http://www.foreignpage.html');
++++//+you+could+also+use+curl+for+more+fancy+internet+queries+or+if+http+wrappers+aren't+active+in+your+php.ini
++++//+parse+$foreignpage+for+data+that+indicates+your+page+should+proceed
++++echo+$foreignpage;+//+or+a+portion+of+it+as+you+parsed
++++exit();++//+this+is+very+important++otherwise+you'll+get+the+contents+of+your+own+page+returned+back+to+you+on+each+call
++}
}
?>

<html>
++mypage+html+content
++...

<script>
var+stopmelater=+setInterval("getforeignurl('?urlget=doesntmatter')",+2000);

function+getforeignurl(url){
++var+handle=+browserspec();
++handle.open('GET',+url,+false);
++handle.send();
++var+returnedPageContents=+handle.responseText;
++//+parse+page+contents+for+what+your+looking+and+trigger+javascript+events+accordingly.
++//+use+handle.open('GET',+url,+true)+to+allow+javascript+to+continue+executing.+must+provide+a+callback+function+to+accept+the+page+contents+with+handle.onreadystatechange()
}
function+browserspec(){
++if+(window.XMLHttpRequest){
++++return+new+XMLHttpRequest();
++}else{
++++return+new+ActiveXObject("Microsoft.XMLHTTP");
++}
}

</script>|code-block|syntax|javascript|1080755|这应该就行了。|1080756|被触发的javascript应该包含clearInterval(停止混音器)|1080757|如果对你有效，请让我知道|1080758|杰瑞|1080759|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

It might be a lot easier than all that. If you want your page to load then check on the availability or content of some foreign page to trigger other web page activity, you could do it using only javascript and php like this. 

yourpage.php

<pre><code>&lt;?php
if (isset($_GET['urlget'])){
 if ($_GET['urlget']!=''){
 $foreignpage= file_get_contents('http://www.foreignpage.html');
 // you could also use curl for more fancy internet queries or if http wrappers aren't active in your php.ini
 // parse $foreignpage for data that indicates your page should proceed
 echo $foreignpage; // or a portion of it as you parsed
 exit(); // this is very important otherwise you'll get the contents of your own page returned back to you on each call
 }
}
?&gt;

&lt;html&gt;
 mypage html content
 ...

&lt;script&gt;
var stopmelater= setInterval("getforeignurl('?urlget=doesntmatter')", 2000);

function getforeignurl(url){
 var handle= browserspec();
 handle.open('GET', url, false);
 handle.send();
 var returnedPageContents= handle.responseText;
 // parse page contents for what your looking and trigger javascript events accordingly.
 // use handle.open('GET', url, true) to allow javascript to continue executing. must provide a callback function to accept the page contents with handle.onreadystatechange()
}
function browserspec(){
 if (window.XMLHttpRequest){
 return new XMLHttpRequest();
 }else{
 return new ActiveXObject("Microsoft.XMLHTTP");
 }
}

&lt;/script&gt;
</code></pre>

That should do it.

The triggered javascript should include clearInterval(stopmelater)

Let me know if that works for you

Jerry

blocks|key|866138|text|只需替换|type|unstyled|depth|inlineStyleRanges|entityRanges|data|866139|file_get_contents|code-block|syntax|javascript|866140|使用|866141|$ip+=+$_SERVER['xxx.xxx.xxx.xxx'];
exec("ping+-n+4+$ip+2>&1",+$output,+$retval);
if+($retval+!=+0)+{+
++echo+"no!";+
}+
else{+
++echo+"yes!";+
}|866142|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

just replace

<pre><code>file_get_contents
</code></pre>

with

<pre><code>$ip = $_SERVER['xxx.xxx.xxx.xxx'];
exec("ping -n 4 $ip 2&gt;&amp;1", $output, $retval);
if ($retval != 0) { 
 echo "no!"; 
} 
else{ 
 echo "yes!"; 
}
</code></pre>

blocks|key|1080815|text|Ping是ICMP，但如果远程服务器上有任何开放的TCP端口，则可以这样实现：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080816|​|1080817|function+ping(host,+port,+pong)+{

++var+started+=+new+Date().getTime();

++var+http+=+new+XMLHttpRequest();

++http.open("GET",+"http://"+%2B+host+%2B+":"+%2B+port,+/*async*/true);
++http.onreadystatechange+=+function()+{
++++if+(http.readyState+==+4)+{
++++++var+ended+=+new+Date().getTime();

++++++var+milliseconds+=+ended+-+started;

++++++if+(pong+!=+null)+{
++++++++pong(milliseconds);
++++++}
++++}
++};
++try+{
++++http.send(null);
++}+catch(exception)+{
++++//+this+is+expected
++}

}|code-block|syntax|javascript|1080818|1080819|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$G|H]]|$1|I|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|K|$]]

Ping is ICMP, but if there is any open TCP port on the remote server it could be achieved like this:



<pre><code>function ping(host, port, pong) {

 var started = new Date().getTime();

 var http = new XMLHttpRequest();

 http.open("GET", "http://" + host + ":" + port, /*async*/true);
 http.onreadystatechange = function() {
 if (http.readyState == 4) {
 var ended = new Date().getTime();

 var milliseconds = ended - started;

 if (pong != null) {
 pong(milliseconds);
 }
 }
 };
 try {
 http.send(null);
 } catch(exception) {
 // this is expected
 }

}
</code></pre>

blocks|key|1080849|text|使用websocket解决方案...|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080850|function+ping(ip,+isUp,+isDown)+{
++var+ws+=+new+WebSocket("ws://"+%2B+ip);
++ws.onerror+=+function(e){
++++isUp();
++++ws+=+null;
++};
++setTimeout(function()+{+
++++if(ws+!=+null)+{
++++++ws.close();
++++++ws+=+null;
++++++isDown();
++++}
++},2000);
}|code-block|syntax|javascript|1080851|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Pitching in with a websocket solution...

<pre><code>function ping(ip, isUp, isDown) {
 var ws = new WebSocket("ws://" + ip);
 ws.onerror = function(e){
 isUp();
 ws = null;
 };
 setTimeout(function() { 
 if(ws != null) {
 ws.close();
 ws = null;
 isDown();
 }
 },2000);
}
</code></pre>

blocks|key|1080915|text|您可以使用以下命令从javaScript运行DOS+ping.exe命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1080916|function+ping(ip)
{
++++var+input+=+"";
++++var+WshShell+=+new+ActiveXObject("WScript.Shell");
++++var+oExec+=+WshShell.Exec("c:/windows/system32/ping.exe+"+%2B+ip);

++++while+(!oExec.StdOut.AtEndOfStream)
++++{
++++++++++++input+%2B=+oExec.StdOut.ReadLine()+%2B+"<br+/>";
++++}
++++return+input;
}|code-block|syntax|javascript|1080917|这是要求的吗，还是我漏掉了什么？|1080918|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can run the DOS ping.exe command from javaScript using the folowing:

<pre><code>function ping(ip)
{
 var input = "";
 var WshShell = new ActiveXObject("WScript.Shell");
 var oExec = WshShell.Exec("c:/windows/system32/ping.exe " + ip);

 while (!oExec.StdOut.AtEndOfStream)
 {
 input += oExec.StdOut.ReadLine() + "&lt;br /&gt;";
 }
 return input;
}
</code></pre>

Is this what was asked for, or am i missing something?

blocks|key|1081001|text|如果您尝试查看的是服务器是否“存在”，则可以使用以下方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1081002|function+isValidURL(url)+{
++++var+encodedURL+=+encodeURIComponent(url);
++++var+isValid+=+false;

++++$.ajax({
++++++url:+"http://query.yahooapis.com/v1/public/yql?q=select%2520*%2520from%2520html%2520where%2520url%253D%2522"+%2B+encodedURL+%2B+"%2522&format=json",
++++++type:+"get",
++++++async:+false,
++++++dataType:+"json",
++++++success:+function(data)+{
++++++++isValid+=+data.query.results+!=+null;
++++++},
++++++error:+function(){
++++++++isValid+=+false;
++++++}
++++});

++++return+isValid;
}|code-block|syntax|javascript|1081003|这将返回服务器是否存在的真/假指示。|1081004|如果你想要响应时间，稍微修改一下就可以了：|1081005|function+ping(url)+{
++++var+encodedURL+=+encodeURIComponent(url);
++++var+startDate+=+new+Date();
++++var+endDate+=+null;
++++$.ajax({
++++++url:+"http://query.yahooapis.com/v1/public/yql?q=select%2520*%2520from%2520html%2520where%2520url%253D%2522"+%2B+encodedURL+%2B+"%2522&format=json",
++++++type:+"get",
++++++async:+false,
++++++dataType:+"json",
++++++success:+function(data)+{
++++++++if+(data.query.results+!=+null)+{
++++++++++++endDate+=+new+Date();
++++++++}+else+{
++++++++++++endDate+=+null;
++++++++}
++++++},
++++++error:+function(){
++++++++endDate+=+null;
++++++}
++++});

++++if+(endDate+==+null)+{
++++++++throw+"Not+responsive...";
++++}

++++return+endDate.getTime()+-+startDate.getTime();
}|1081006|这样用法就很简单了：|1081007|var+isValid+=+isValidURL("http://example.com");
alert(isValid+?+"Valid+URL!!!"+:+"Damn...");|1081008|或者：|1081009|var+responseInMillis+=+ping("example.com");
alert(responseInMillis);|1081010|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

If what you are trying to see is whether the server "exists", you can use the following:

<pre><code>function isValidURL(url) {
 var encodedURL = encodeURIComponent(url);
 var isValid = false;

 $.ajax({
 url: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22" + encodedURL + "%22&amp;format=json",
 type: "get",
 async: false,
 dataType: "json",
 success: function(data) {
 isValid = data.query.results != null;
 },
 error: function(){
 isValid = false;
 }
 });

 return isValid;
}
</code></pre>

This will return a true/false indication whether the server exists. 

If you want response time, a slight modification will do:

<pre><code>function ping(url) {
 var encodedURL = encodeURIComponent(url);
 var startDate = new Date();
 var endDate = null;
 $.ajax({
 url: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22" + encodedURL + "%22&amp;format=json",
 type: "get",
 async: false,
 dataType: "json",
 success: function(data) {
 if (data.query.results != null) {
 endDate = new Date();
 } else {
 endDate = null;
 }
 },
 error: function(){
 endDate = null;
 }
 });

 if (endDate == null) {
 throw "Not responsive...";
 }

 return endDate.getTime() - startDate.getTime();
}
</code></pre>

The usage is then trivial:

<pre><code>var isValid = isValidURL("http://example.com");
alert(isValid ? "Valid URL!!!" : "Damn...");
</code></pre>

Or:

<pre><code>var responseInMillis = ping("example.com");
alert(responseInMillis);
</code></pre>

blocks|key|1081068|text|这里有很多疯狂的答案，特别是关于CORS+-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1081069|您可以执行http+HEAD请求(如GET，但没有有效负载)。请参阅https://ochronus.com/http-head-request-good-uses/|offset|length|1081070|它不需要飞前检查，混乱是由于旧版本的规范，请参阅Why+does+a+cross-origin+HEAD+request+need+a+preflight+check?|1081071|因此，您可以使用上面的答案，即使用jQuery库(没有说明)，但使用|1081072|type:+'HEAD'|code-block|syntax|javascript|1081073|->|1081074|<script>
++++function+ping(){
+++++++$.ajax({
++++++++++url:+'ping.html',
++++++++++type:+'HEAD',
++++++++++success:+function(result){
+++++++++++++alert('reply');
++++++++++},+++++
++++++++++error:+function(result){
++++++++++++++alert('timeout/error');
++++++++++}
+++++++});
++++}
</script>|1081075|当然，您也可以使用香草js或dojo或其他任何东西。|1081076|entityMap|0|LINK|mutability|MUTABLE|url|https://ochronus.com/http-head-request-good-uses/|1|https://stackoverflow.com/questions/22107694/why-does-a-cross-origin-head-request-need-a-preflight-check^0|0|Y|1D|0|0|O|1O|1|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|15|8|@]|9|@$D|16|E|17|1|18]]|A|$]]|$1|F|3|G|5|6|7|19|8|@]|9|@$D|1A|E|1B|1|1C]]|A|$]]|$1|H|3|I|5|6|7|1D|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|1E|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|1F|8|@]|9|@]|A|$]]|$1|Q|3|R|5|L|7|1G|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|1H|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]|12|$5|X|Y|Z|A|$10|13]]]]

There are many crazy answers here and especially about CORS -

You could do an http HEAD request (like GET but without payload).
See <a href="https://ochronus.com/http-head-request-good-uses/" rel="nofollow noreferrer">https://ochronus.com/http-head-request-good-uses/</a>

It does NOT need a preflight check, the confusion is because of an old version of the specification, see
<a href="https://stackoverflow.com/questions/22107694/why-does-a-cross-origin-head-request-need-a-preflight-check">Why does a cross-origin HEAD request need a preflight check?</a>

So you could use the answer above which is using the jQuery library (didn't say it) but with 

<pre><code>type: 'HEAD'
</code></pre>

--->

<pre><code>&lt;script&gt;
 function ping(){
 $.ajax({
 url: 'ping.html',
 type: 'HEAD',
 success: function(result){
 alert('reply');
 }, 
 error: function(result){
 alert('timeout/error');
 }
 });
 }
&lt;/script&gt;
</code></pre>

Off course you can also use vanilla js or dojo or whatever ...

blocks|key|866414|text|let+webSite+=+'https://google.com/'+
https.get(webSite,+function+(res)+{
++++//+If+you+get+here,+you+have+a+response.
++++//+If+you+want,+you+can+check+the+status+code+here+to+verify+that+it's+`200`+or+some+other+`2xx`.
++++console.log(webSite+%2B+'+'+%2B+res.statusCode)
}).on('error',+function(e)+{
++++//+Here,+an+error+occurred.++Check+`e`+for+the+error.
++++console.log(e.code)
});;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|866415|如果你用node运行这个命令，只要google没有关闭，它就会记录200个控制台日志。|unstyled|866416|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>let webSite = 'https://google.com/' 
https.get(webSite, function (res) {
 // If you get here, you have a response.
 // If you want, you can check the status code here to verify that it's `200` or some other `2xx`.
 console.log(webSite + ' ' + res.statusCode)
}).on('error', function(e) {
 // Here, an error occurred. Check `e` for the error.
 console.log(e.code)
});;
</code></pre>

if you run this with node it would console log 200 as long as google is not down.

blocks|key|866425|text|const+ping+=+(url,+timeout+=+6000)+=>+{
++return+new+Promise((resolve,+reject)+=>+{
++++const+urlRule+=+new+RegExp('(https?%7Cftp%7Cfile)://[-A-Za-z0-9%2B&@#/%25?=~_%7C!:,.;]%2B[-A-Za-z0-9%2B&@#/%25=~_%7C]');
++++if+(!urlRule.test(url))+reject('invalid+url');
++++try+{
++++++fetch(url)
++++++++.then(()+=>+resolve(true))
++++++++.catch(()+=>+resolve(false));
++++++setTimeout(()+=>+{
++++++++resolve(false);
++++++},+timeout);
++++}+catch+(e)+{
++++++reject(e);
++++}
++});
};|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|866426|像这样使用：|unstyled|866427|ping('https://stackoverflow.com/')
++.then(res=>console.log(res))
++.catch(e=>console.log(e))|866428|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre class="lang-js prettyprint-override"><code>const ping = (url, timeout = 6000) =&gt; {
 return new Promise((resolve, reject) =&gt; {
 const urlRule = new RegExp('(https?|ftp|file)://[-A-Za-z0-9+&amp;@#/%?=~_|!:,.;]+[-A-Za-z0-9+&amp;@#/%=~_|]');
 if (!urlRule.test(url)) reject('invalid url');
 try {
 fetch(url)
 .then(() =&gt; resolve(true))
 .catch(() =&gt; resolve(false));
 setTimeout(() =&gt; {
 resolve(false);
 }, timeout);
 } catch (e) {
 reject(e);
 }
 });
};
</code></pre>
use like this:
<pre class="lang-js prettyprint-override"><code>ping('https://stackoverflow.com/')
 .then(res=&gt;console.log(res))
 .catch(e=&gt;console.log(e))
</code></pre>

I'm making a web app that requires that I check to see if remote servers are online or not. When I run it from the command line, my page load goes up to a full 60s (for 8 entries, it will scale linearly with more).

I decided to go the route of pinging on the user's end. This way, I can load the page and just have them wait for the "server is online" data while browsing my content.

If anyone has the answer to the above question, or if they know a solution to keep my page loads fast, I'd definitely appreciate it.

Is it possible to ping a server from Javascript?

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我正在制作一个web应用程序，它需要我检查远程服务器是否在线。当我从命令行运行它时，我的页面加载达到了整整60秒(对于8个条目，它将随着更多条目而线性扩展)。我决定走在用户端执行pinging命令的路线。这样，我就可以加载页面，让他们在浏览我的内容时等待“服务器在线”数据。如果有人对上面的问题有答案，或者如果他们知道保...

问是否可以从Javascript ping服务器？
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