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---
title: MessageChannel
slug: Web/API/MessageChannel
tags:
- API
- Channel Messaging API
- Interface
- MessageChannel
- Reference
- web messaging
translation_of: Web/API/MessageChannel
---
<p>{{APIRef("HTML DOM")}}</p>
<p>Channel Messaging API的<strong><code>MessageChannel</code></strong> 接口允许我们创建一个新的消息通道，并通过它的两个{{domxref("MessagePort")}} 属性发送数据。</p>
<p>{{AvailableInWorkers}}</p>
<h2 id="属性">属性</h2>
<dl>
<dt>{{domxref("MessageChannel.port1")}} {{readonlyInline}}</dt>
<dd>返回channel的port1。</dd>
<dt>{{domxref("MessageChannel.port2")}} {{readonlyInline}}</dt>
<dd>返回channel的port2。</dd>
</dl>
<h2 id="构造函数">构造函数</h2>
<dl>
<dt>{{domxref("MessageChannel.MessageChannel", "MessageChannel()")}}</dt>
<dd>
<p>返回一个带有两个MessagePort属性的MessageChannel新对象。</p>
</dd>
</dl>
<h2 id="示例">示例</h2>
<p>在以下代码块中，您可以看到使用MessageChannel构造函数实例化了一个channel对象。当iframe加载完毕，我们使用MessagePort.postMessage方法把一条消息和MessageChannel.port2传递给iframe。handleMessage处理程序将会从iframe中（使用MessagePort.onmessage监听事件）接收到信息，将数据其放入innerHTML中。</p>
<pre class="brush: js">var channel = new MessageChannel();
var para = document.querySelector('p');
var ifr = document.querySelector('iframe');
var otherWindow = ifr.contentWindow;
ifr.addEventListener("load", iframeLoaded, false);
function iframeLoaded() {
otherWindow.postMessage('Hello from the main page!', '*', [channel.port2]);
}
channel.port1.onmessage = handleMessage;
function handleMessage(e) {
para.innerHTML = e.data;
} </pre>
<p>一个完整的运行示例，可以在Github上查看 <a class="external external-icon" href="https://github.com/mdn/dom-examples/tree/master/channel-messaging-basic">channel messaging basic demo</a> (<a class="external external-icon" href="https://mdn.github.io/dom-examples/channel-messaging-basic/">run it live too</a>).</p>
<h2 id="Specifications规范">Specifications/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('HTML WHATWG', '#message-channels','MessageChannel')}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td>No difference from {{SpecName("HTML5 Web Messaging")}}.</td>
</tr>
</tbody>
</table>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<div>{{Compat("api.MessageChannel")}}</div>
<div id="compat-mobile"></div>
<h2 id="参见">参见</h2>
<ul>
<li><a href="/en-US/docs/Web/API/Channel_Messaging_API/Using_channel_messaging">Using channel messaging</a></li>
</ul>
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