blob: 7f4a3b7079680e6bc5fe69b97f3c9581fad51f11 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
---
title: MessageChannel.port2
slug: Web/API/MessageChannel/port2
translation_of: Web/API/MessageChannel/port2
---
<p>{{APIRef("HTML DOM")}}</p>
<p>{{domxref("MessageChannel")}}接口的 <code><strong>port2</strong></code> 是一个只读属性，返回消息通道的第二个端口，该端口连接到通道另一端的上下文，也就是发送消息时的目的地。</p>
<p>{{AvailableInWorkers}}</p>
<h2 id="语法">语法</h2>
<pre class="syntaxbox">channel.port2;</pre>
<h3 id="值">值</h3>
<p>表示通道第二个端口的一个{{domxref("MessagePort")}}对象，该端口附加到通道另一端的上下文。</p>
<p> </p>
<h2 id="示例">示例</h2>
<p>如下代码所示，通过{{domxref("MessageChannel()", "MessageChannel.MessageChannel")}}构造函数创建了一个新的通道。当IFrame加载完毕，我们使用{{domxref("MessagePort.postMessage")}}将一条消息以及port2传递给IFrame。handleMessage处理程序响应从IFrame发回的消息（使用 {{domxref("MessagePort.onmessage")}}），将其放入段落中。{{domxref("MessageChannel.port1")}}已经监听，以检测消息何时到达。</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>有关完整的运行示例，请参阅我们在GitHub的 <a class="external external-icon" href="https://github.com/mdn/channel-messaging-basic-demo">channel messaging basic demo</a> (<a class="external external-icon" href="http://mdn.github.io/channel-messaging-basic-demo/">run it live too</a>).</p>
<h2 id="Specifications">Specifications</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', 'web-messaging.html#dom-messagechannel-port2', 'port2')}}</td>
<td>{{Spec2('HTML WHATWG')}}</td>
<td> </td>
</tr>
</tbody>
</table>
<h2 id="Browser_compatibility">Browser compatibility</h2>
<div>{{CompatibilityTable}}</div>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Edge</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari (WebKit)</th>
</tr>
<tr>
<td>Basic support</td>
<td>4</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatGeckoDesktop(41)}}</td>
<td>10.0</td>
<td>10.6</td>
<td>5</td>
</tr>
<tr>
<td>Available in workers</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatUnknown}}</td>
<td>{{CompatGeckoDesktop(41)}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Chrome for Android</th>
<th>Edge</th>
<th>Firefox Mobile (Gecko)</th>
<th>Firefox OS (Gecko)</th>
<th>IE Phone</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td>4.4</td>
<td>4</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatGeckoMobile(41)}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>10.0</td>
<td>11.5</td>
<td>5.1</td>
</tr>
<tr>
<td>Available in workers</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatUnknown}}</td>
<td>{{CompatGeckoMobile(41)}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
<td>{{CompatVersionUnknown}}</td>
</tr>
</tbody>
</table>
</div>
<h2 id="See_also">See also</h2>
<ul>
<li><a href="/en-US/docs/Web/API/Channel_Messaging_API/Using_channel_messaging">Using channel messaging</a></li>
</ul>
|
