title: Chrome sendrequest error: TypeError: Converting circular structure to JSON
body: <p>I've got the following...</p>
  
  <pre><code>chrome.extension.sendRequest({
    req: "getDocument",
    docu: pagedoc,
    name: 'name'
  }, function(response){
    var efjs = response.reply;
  });
  </code></pre>
  
  <p>which calls the following..</p>
  
  <pre><code>case "getBrowserForDocumentAttribute":
    alert("ZOMG HERE");
    sendResponse({
      reply: getBrowserForDocumentAttribute(request.docu,request.name)
    });
    break;
  </code></pre>
  
  <p>However, my code never reaches "ZOMG HERE" but rather throws the following error while running <code>chrome.extension.sendRequest</code></p>
  
  <pre><code> Uncaught TypeError: Converting circular structure to JSON
   chromeHidden.JSON.stringify
   chrome.Port.postMessage
   chrome.initExtension.chrome.extension.sendRequest
   suggestQuery
  </code></pre>
  
  <p>Does anyone have any idea what is causing this?</p>