title: "(Callback method) is not defined" in JSONP access on Firefox Addon
body: <p>I'm trying to get data from server using JSONP with jQuery's ajax method.</p>
  
  <pre><code>$.ajax({
      dataType: "jsonp",
      url: "https://secure.flickr.com/services/feeds/photos_public.gne?tags=cat&amp;tagmode=any&amp;format=json",
      type: "GET",
      data: "msg=aaa",
      cache: true,
      jsonp: "jsoncallback",
      // jsonpCallback: "callbackmethod",
  
      success: function(encryptedMsg){
          console.log("Encryption success!");
      },
      error: function(req, errmsg, thrownError) {
          console.log("Error: HTTP " + req.status + " " + errmsg);
      }
  });
  </code></pre>
  
  <p>However, following error is shown in error console:</p>
  
  <pre><code>Error: jQuery1720502636097747291_1339479763752 is not defined
  Source File: https://secure.flickr.com/services/feeds/photos_public.gne?tags=cat&amp;tagmode=any&amp;format=json&amp;jsoncallback=jQuery1720502636097747291_1339479763752&amp;msg=aaa
  Line: 1
  </code></pre>
  
  <p>If you open the source file URL, you can see following JSON, and it seems correct JSON.</p>
  
  <pre><code>jQuery1720502636097747291_1339479763752({
      "title": "Recent Uploads tagged cat",
      // ...
      "items": [
      {
          "title": "Chaton",
          // ...
      },
      // ...
      ]
  })
  </code></pre>
  
  <p>I also tried to specify method name with jsonpCallback: "callbackmethod", but it didn't work.
  I also used $.getJson() method and jquery-jsonp (http://code.google.com/p/jquery-jsonp/) but the result was the same.</p>
  
  <p>The browser is Firefox and using HTML4.
  This is used in a firefox addon.</p>
  
  <p>You can read full code here: <a href="https://builder.addons.mozilla.org/addon/1048275/revision/749" rel="nofollow">https://builder.addons.mozilla.org/addon/1048275/revision/749</a><br>
  I use $.ajax in getEncryptedMessage function in common-content.js</p>
  
  <p>Thanks in advance.</p>