files/zh-cn/web/api/htmlmediaelement/readystate/index.html


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---
title: HTMLMediaElement.readyState
slug: Web/API/HTMLMediaElement/readyState
translation_of: Web/API/HTMLMediaElement/readyState
---
<div>{{APIRef("HTML DOM")}}</div>

<p><strong><code>HTMLMediaElement.readyState </code></strong>属性返回音频/视频的当前就绪状态。</p>

<h2 id="Syntax" name="Syntax">语法</h2>

<pre class="syntaxbox">var readyState = audioOrVideo.readyState;</pre>

<h3 id="返回值">返回值</h3>

<p>无符号整型 An <code>unsigned short</code>.</p>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Constant</th>
   <th scope="col">Value</th>
   <th scope="col">Description</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>HAVE_NOTHING</td>
   <td>0</td>
   <td>没有关于音频/视频是否就绪的信息</td>
  </tr>
  <tr>
   <td>HAVE_METADATA</td>
   <td>1</td>
   <td>音频/视频已初始化</td>
  </tr>
  <tr>
   <td>HAVE_CURRENT_DATA</td>
   <td>2</td>
   <td>数据已经可以播放(当前位置已经加载) 但没有数据能播放下一帧的内容</td>
  </tr>
  <tr>
   <td>HAVE_FUTURE_DATA</td>
   <td>3</td>
   <td>当前及至少下一帧的数据是可用的(换句话来说至少有两帧的数据)</td>
  </tr>
  <tr>
   <td>HAVE_ENOUGH_DATA</td>
   <td>4</td>
   <td> 可用数据足以开始播放-如果网速得到保障 那么视频可以一直播放到底</td>
  </tr>
 </tbody>
</table>

<h2 id="实例">实例</h2>

<p>这个例子会监听id为example的 audio 的数据. 他会检查当前位置是否可以播放, 会的话执行播放。</p>

<pre class="brush: html">&lt;audio id="example" preload="auto"&gt;
 &lt;source src="sound.ogg" type="audio/ogg" /&gt;
&lt;/audio&gt;

</pre>

<pre class="brush: js">var obj = document.getElementById('example');

obj.addEventListener('loadeddata', function() {

  if(obj.readyState &gt;= 2) {
    obj.play();
  }

});
</pre>

<p> </p>

<h2 id="参考文档">参考文档</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('HTML WHATWG', "the-video-element.html#htmlmediaelement", "HTMLMediaElement.readyState")}}</td>
   <td>{{Spec2('HTML WHATWG')}}</td>
   <td>No change from {{SpecName('HTML5 W3C')}}</td>
  </tr>
  <tr>
   <td>{{SpecName('HTML5 W3C', "embedded-content-0.html#htmlmediaelement", "HTMLMediaElement.readyState")}}</td>
   <td>{{Spec2('HTML5 W3C')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<h2 id="浏览器兼容性">浏览器兼容性</h2>

<p>{{ CompatibilityTable() }}</p>

<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</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoDesktop("1.9.1")}} [1]</td>
   <td>{{CompatIE("9")}}</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 (Gecko)</th>
   <th>IE Mobile</th>
   <th>Opera Mobile</th>
   <th>Safari Mobile</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<p>[1] The <code>NETWORK_LOADED</code> state was removed to align with the HTML spec in Gecko 2.0 {{geckoRelease(2)}}. </p>

<h2 id="See_Also" name="See_Also">你或许还可以看看</h2>

<ul>
 <li>The interface defining it, {{domxref("HTMLMediaElement")}}.</li>
</ul>