我一直在开发基于浏览器的多人游戏一段时间，并且一直在测试各种环境（客户办公室、公共 wifi 等）中的不同端口可访问性。一切都很顺利，除了一件事：我不知道如何阅读错误号。或接收到 onerror 事件时的描述。
客户端 websocket 是用 javascript 完成的。
例如：
// Init of websocket
websocket = new WebSocket(wsUri);
websocket.onerror = OnSocketError;
...etc...
// Handler for onerror:
function OnSocketError(ev)
{
output("Socket error: " + ev.data);
}
“输出”只是一些写入 div 的实用函数。
我得到的是 ev.data 的“未定义”。总是。我一直在谷歌搜索，但似乎没有关于这个事件有什么参数以及如何正确阅读它的规范。
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除了 nmaier 的回答，正如他所说，您将始终收到代码 1006。但是，如果您在理论上以某种方式接收其他代码，这里是显示结果的代码（通过RFC6455）。
var websocket;
if ("WebSocket" in window)
{
websocket = new WebSocket("ws://yourDomainNameHere.org/");
websocket.onopen = function (event) {
$("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was opened");
};
websocket.onclose = function (event) {
var reason;
alert(event.code);
// See https://www.rfc-editor.org/rfc/rfc6455#section-7.4.1
if (event.code == 1000)
reason = "Normal closure, meaning that the purpose for which the connection was established has been fulfilled.";
else if(event.code == 1001)
reason = "An endpoint is \"going away\", such as a server going down or a browser having navigated away from a page.";
else if(event.code == 1002)
reason = "An endpoint is terminating the connection due to a protocol error";
else if(event.code == 1003)
reason = "An endpoint is terminating the connection because it has received a type of data it cannot accept (e.g., an endpoint that understands only text data MAY send this if it receives a binary message).";
else if(event.code == 1004)
reason = "Reserved. The specific meaning might be defined in the future.";
else if(event.code == 1005)
reason = "No status code was actually present.";
else if(event.code == 1006)
reason = "The connection was closed abnormally, e.g., without sending or receiving a Close control frame";
else if(event.code == 1007)
reason = "An endpoint is terminating the connection because it has received data within a message that was not consistent with the type of the message (e.g., non-UTF-8 [https://www.rfc-editor.org/rfc/rfc3629] data within a text message).";
else if(event.code == 1008)
reason = "An endpoint is terminating the connection because it has received a message that \"violates its policy\". This reason is given either if there is no other sutible reason, or if there is a need to hide specific details about the policy.";
else if(event.code == 1009)
reason = "An endpoint is terminating the connection because it has received a message that is too big for it to process.";
else if(event.code == 1010) // Note that this status code is not used by the server, because it can fail the WebSocket handshake instead.
reason = "An endpoint (client) is terminating the connection because it has expected the server to negotiate one or more extension, but the server didn't return them in the response message of the WebSocket handshake. <br /> Specifically, the extensions that are needed are: " + event.reason;
else if(event.code == 1011)
reason = "A server is terminating the connection because it encountered an unexpected condition that prevented it from fulfilling the request.";
else if(event.code == 1015)
reason = "The connection was closed due to a failure to perform a TLS handshake (e.g., the server certificate can't be verified).";
else
reason = "Unknown reason";
$("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "The connection was closed for reason: " + reason);
};
websocket.onmessage = function (event) {
$("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "New message arrived: " + event.data);
};
websocket.onerror = function (event) {
$("#thingsThatHappened").html($("#thingsThatHappened").html() + "<br />" + "There was an error with your websocket.");
};
}
else
{
alert("Websocket is not supported by your browser");
return;
}
websocket.send("Yo wazzup");
websocket.close();
处理程序收到的错误Event是一个不包含此类信息的简单事件：onerror
如果要求用户代理使 WebSocket 连接失败或 WebSocket 连接因偏见而关闭，则在 WebSocket 对象上触发一个名为 error 的简单事件。
您可能会更幸运地监听该close事件，该事件是一个CloseEvent并且确实具有CloseEvent.code包含根据RFC 6455 11.7的数字代码和CloseEvent.reason字符串属性的属性。
但是请注意，CloseEvent.code（和CloseEvent.reason）受到限制，以避免网络探测和其他安全问题。
对于那些不顾一切的人来说可能是愚蠢的解决方法：返回一个状态码。通过访问处理程序接收的参数的属性，可以从onerror事件处理程序查看状态代码。message我建议使用 440s——似乎是免费的房地产。
一点点正则表达式就可以了：
const socket = new WebSocket(/* yuh */);
socket.onerror = e => {
const errorCode = e.message.match(/\d{3}/)[0];
// errorCode = '440'
// make your own rudimentary standard for error codes and handle them accordingly
};
可能在紧要关头有用，但不要因为任何不可预见的后果而向我哭泣。