title: Site's API is not defined
body: <p>I'm trying to acces the <a href="http://blog.plug.dj/api-documentation/" rel="nofollow">plug.dj API</a> from an Chrome extension but everytime I type <code>API.bar()</code> it gives me:</p>
  
  <blockquote>
    <p>Uncaught ReferenceError: API is not defined</p>
  </blockquote>
  
  <p>I use the following manifest.json</p>
  
  <pre><code>{
     "content_scripts": [ {
        "js": [
           "jquery.js",
           "lastfm.api.md5.js", 
           "lastfm.api.js",
           "script.js"
        ],
        "css": [ "LastFMLink.css" ],
        "matches": [ 
           "http://plug.dj/*", 
           "http://plug.dj/*/*"
           ],
        "run_at": "document_end"
     } 
     ],
  
     "name": "Plug.Dj VS last.Fm",
     "description": "Implement information about the artist",
     "icons": { "16": "cookie.png", "48": "cookie.png", "128": "cookie.png" },
     "permissions": [ 
        "http://plug.dj/*", 
        "http://plug.dj/*/*"
     ],
     "version": "1.0.0",
     "web_accessible_resources": ["script.js"],
     "manifest_version": 2
  }
  </code></pre>
  
  <p>anyone knows what I might be doing wrong? or forgetting?</p>