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+---
+title: AudioContext.createAnalyser()
+slug: Web/API/AudioContext/createAnalyser
+translation_of: Web/API/BaseAudioContext/createAnalyser
+---
+<p>{{ APIRef("Web Audio API") }}</p>
+
+<div>
+<p>{{ domxref("AudioContext") }}的<code>createAnalyser()</code>方法能创建一个{{ domxref("AnalyserNode") }}，可以用来获取音频时间和频率数据，以及实现数据可视化。</p>
+</div>
+
+<div class="note">
+<p><strong>注意</strong>：关于该节点的更多信息，请查看{{domxref("AnalyserNode")}}</p>
+</div>
+
+<h2 id="语法">语法</h2>
+
+<pre class="brush: js">var audioCtx = new AudioContext();
+var analyser = audioCtx.createAnalyser();</pre>
+
+<h3 id="Description" name="Description">返回值</h3>
+
+<p>{{domxref("AnalyserNode")}}对象</p>
+
+<h2 id="Examples" name="Examples">例子</h2>
+
+<p>下面的例子展示了AudioContext创建分析器节点的基本用法，然后用requestAnimationFrame()来反复获取时域数据，并绘制出当前音频输入的“示波器风格”输出。更多完整例子请查看<a href="https://mdn.github.io/voice-change-o-matic/">Voice-change-O-matic</a> demo (中<a href="https://github.com/mdn/voice-change-o-matic/blob/gh-pages/scripts/app.js#L128-L205">app.js的128–205行</a>代码)</p>
+
+<pre class="brush: js">var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
+var analyser = audioCtx.createAnalyser();
+
+  ...
+
+analyser.fftSize = 2048;
+var bufferLength = analyser.fftSize;
+var dataArray = new Uint8Array(bufferLength);
+analyser.getByteTimeDomainData(dataArray);
+
+// draw an oscilloscope of the current audio source
+
+function draw() {
+
+      drawVisual = requestAnimationFrame(draw);
+
+      analyser.getByteTimeDomainData(dataArray);
+
+      canvasCtx.fillStyle = 'rgb(200, 200, 200)';
+      canvasCtx.fillRect(0, 0, WIDTH, HEIGHT);
+
+      canvasCtx.lineWidth = 2;
+      canvasCtx.strokeStyle = 'rgb(0, 0, 0)';
+
+      canvasCtx.beginPath();
+
+      var sliceWidth = WIDTH * 1.0 / bufferLength;
+      var x = 0;
+
+      for(var i = 0; i &lt; bufferLength; i++) {
+
+        var v = dataArray[i] / 128.0;
+        var y = v * HEIGHT/2;
+
+        if(i === 0) {
+          canvasCtx.moveTo(x, y);
+        } else {
+          canvasCtx.lineTo(x, y);
+        }
+
+        x += sliceWidth;
+      }
+
+      canvasCtx.lineTo(canvas.width, canvas.height/2);
+      canvasCtx.stroke();
+    };
+
+    draw();</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-createAnalyser-AnalyserNode', 'createAnalyser()')}}</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(10.0)}}{{property_prefix("webkit")}}</td>
+   <td>{{CompatGeckoDesktop(25.0)}} </td>
+   <td>{{CompatNo}}</td>
+   <td>15.0{{property_prefix("webkit")}}<br>
+    22</td>
+   <td>6.0{{property_prefix("webkit")}}</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>26.0</td>
+   <td>1.2</td>
+   <td>{{CompatUnknown}}</td>
+   <td>{{CompatUnknown}}</td>
+   <td>{{CompatUnknown}}</td>
+   <td>33.0</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>