title: Use chrome.extension.getBackgroundPage() to play an audio file
body: <p>I’m trying to develop a basic Chrome extension that plays a sound, based on a speech input event (everything happens in the background).</p>
  
  <p>Here’s my manifest</p>
  
  <pre><code>{
    "manifest_version" : 2,
    "name"             : "Test123",
    "version"          : "1.0",
    "description"      : "My audio extension",
  
    "icons"            : {
      "128"              : "icon.jpg"
    },
  
    "permissions"      : [
      "experimental",
      "background"
    ],
  
    "background"       : {
      "persistent"       : true,
      "scripts"          : [
        "bg.js"
      ]
    },
  }
  </code></pre>
  
  <p>In <code>bg.js</code>, I get the <code>window</code> object with <code>var chrome.extension.getBackgroundPage();</code>, but I can’t figure what to do from there.</p>
  
  <p>How can I play an audio file?</p>