通过 Channel Messaging API的「MessageChannel」，实现iframe与主页面的双通讯

demo地址：https://mdn.github.io/dom-examples/channel-messaging-basic/

原文来自：https://developer.mozilla.org/zh-CN/docs/Web/API/MessageChannel

index.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport" content="width=device-width">
    <title>Channel messaging demo</title>
    <link rel="stylesheet" href="">
    <!--[if lt IE 9]>
      <script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->
  </head>
  <body>
    <h1>Channel messaging demo</h1>
    <p class="output">My body</p>
    <iframe src="./page.html" width='480' height='320'></iframe>
  </body>
  <script>
    var channel = new MessageChannel();
    var output = document.querySelector('.output');
    var iframe = document.querySelector('iframe');

    // Wait for the iframe to load
    iframe.addEventListener("load", onLoad);
    
    function onLoad() {
      // Listen for messages on port1
      channel.port1.onmessage = onMessage;
      // Transfer port2 to the iframe
      iframe.contentWindow.postMessage('Hello from the main page!', '*', [channel.port2]);
    }

    // Handle messages received on port1
    function onMessage(e) {
      output.innerHTML = e.data;
    }
  </script>
</html>

page.html (iframe嵌入的页面)

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport" content="width=device-width">
    <title>My page title</title>
    <link rel="stylesheet" href="">
    <!--[if lt IE 9]>
      <script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->
  </head>
  <body>
    <p class="output">iFrame body</p>
  </body>
  <script>
  var output = document.querySelector('.output');

  window.addEventListener('message', onMessage);
  
  function onMessage(e) {
      output.innerHTML = e.data;
    // Use the transfered port to post a message back to the main frame
      e.ports[0].postMessage('Message back from the IFrame');
  }
  </script>
</html>

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原文地址：https://www.cnblogs.com/liujinyu/p/13927105.html