---
title: AudioContext.onstatechange
slug: Web/API/BaseAudioContext/statechange_event
translation_of: Web/API/BaseAudioContext/onstatechange
original_slug: Web/API/BaseAudioContext/onstatechange
---
<p>{{ APIRef("Web Audio API") }}</p>

<div>
<p>{{ domxref("AudioContext") }}的<code>onstatechange属性定义了一个事件处理器函数，触发</code>{{Event("statechange")}}会被调用，也就是说audio context的状态发生变化时会执行。</p>
</div>

<h2 id="语法">语法</h2>

<pre class="brush: js">var audioCtx = new AudioContext();
audioCtx.onstatechange = function() { ... };</pre>

<h2 id="例子">例子</h2>

<p>下面这段代码是<a href="https://github.com/mdn/audiocontext-states/settings">AudioContext states DEMO</a> (<a href="http://mdn.github.io/audiocontext-states/">直接运行</a>)中的，其中<code>onstatechange处理器会在每次</code><span style="font-family: courier,andale mono,monospace;">当前</span>{{domxref("state")}}发生变化时<code>把它</code><span style="line-height: 1.5;">输出到控制台。</span></p>

<pre class="brush: js">audioCtx.onstatechange = function() {
  console.log(audioCtx.state);
}
</pre>

<h2 id="规范">规范</h2>

<table class="standard-table">
 <tbody>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
  <tr>
   <td>{{SpecName('Web Audio API', '#widl-AudioContext-onstatechange', 'onstatechange')}}</td>
   <td>{{Spec2('Web Audio API')}}</td>
   <td> </td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

<div>{{CompatibilityTable}}</div>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari (WebKit)</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatChrome(43.0)}}</td>
   <td>{{CompatGeckoDesktop(40.0)}} </td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Firefox Mobile (Gecko)</th>
   <th>Firefox OS</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
   <th>Chrome for Android</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="另见">另见</h2>

<ul>
 <li><a href="/en-US/docs/Web_Audio_API/Using_Web_Audio_API">Using the Web Audio API</a></li>
</ul>