title: Popup script and content script can't communicate?
body: <p>My problem is that I can't seem to get the message <code>chrome.extension.sendMessage("on");</code> from my popup.js transfer to my content.js.</p>
  
  <p>Code from the popup.js:</p>
  
  <pre><code>function click(e) {
      if ( e.target.id == "green"){
          chrome.extension.sendMessage("start");
          console.info("oN");
          return;
      }
  
      if ( e.target.id == "red"){
          chrome.extension.sendMessage("stop");
          console.info("oFF");
          return;
      }
  }
  </code></pre>
  
  <p>The popup.js receives the message perfectly well when i add a listener to the code. But my content.js can't seem to get it.</p>
  
  <p>Code from the content.js:</p>
  
  <pre><code>chrome.extension.onMessage.addListener(
      function(request, sender, sendResponse) {
          console.info("ok");
      }
  );
  </code></pre>
  
  <p>Manifest:</p>
  
  <pre><code>"content_scripts": [
  {
      "matches": ["&lt;all_urls&gt;"],
      "js": ["content.js"],
      "run_at": "document_end"
  }
  ],
  </code></pre>
  
  <p>Any help is greatly appreciated.</p>