title: DOM object not becoming a jQuery object
body: <p>How come I cannot make $(frame) a jQuery object in the below case?
  Below is my output from chrome developer tools.</p>
  
  <pre><code>console: mainFrame
  output: &lt;frame src=​"http:​/​/someurl.com" name=​"mainFrame"&gt;​
  console: $(mainFrame).contents()
  output: SyntaxError: Failed to execute 'querySelector' on 'Document': '[object HTMLFrameElement]' is not a valid selector.
  </code></pre>
  
  <p><strong>Edit:</strong></p>
  
  <p>to respond to comments...</p>
  
  <pre><code>$.toString()
  "function $(selector, [startNode]) { [Command Line API] }"
  
  typeof(mainFrame)
  "object"
  
  jQuery
  ReferenceError: jQuery is not defined
  </code></pre>