title: why I can't send function to content script with sendMessage
body: <p>I'm sending the following message to content script:</p>
  
  <pre><code>chrome.tabs.sendMessage(activeTabId, {
      name:'executePageScript', 
      word:word, 
      isFirst:isFirst, 
      jq: function() {}
  });
  </code></pre>
  
  <p>And listening to it in content script:</p>
  
  <pre><code>chrome.runtime.onMessage.addListener(function(message, sender, sendResponse) {})
  </code></pre>
  
  <p>The problem is that <code>message</code> object contains all keys except for the <code>jq</code> which holds reference to the function expression. If I change function expression to numerical or string literal, like this <code>jq:3</code> or <code>jq:"string"</code>, then the <code>jq</code> key is available in the <code>message</code> object. So it seems that I can't send function expressions (pointers to functions) to content script. Is it true? Or am I missing something?</p>