---
title: WebSocket.onclose
slug: Web/API/WebSocket/onclose
translation_of: Web/API/WebSocket/onclose
---
<p>{{APIRef("Web Sockets API")}}</p>

<p><code><strong>WebSocket.onclose</strong></code> プロパティは、WebSocket コネクションの {{domxref("WebSocket.readyState","readyState")}} が {{domxref("WebSocket.readyState","CLOSED")}} に変わったときに呼ばれる {{event("Event_handlers", "event handler")}} です。{{domxref("CloseEvent")}} と一緒に呼び出されます。</p>

<h2 id="構文">構文</h2>

<pre class="syntaxbox notranslate"><em>aWebSocket</em>.onclose = function(event) {
  console.log("WebSocket is closed now.");
};</pre>

<h2 id="値">値</h2>

<p>{{domxref("EventListener")}}.</p>

<h2 id="仕様書">仕様書</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('HTML WHATWG', '#handler-websocket-onclose', 'WebSocket: onclose')}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>Initial definition</td>
  </tr>
 </tbody>
</table>