title: jQuery POST request from inside an iFrame times out
body: <p>I have an iframe that is injected into an arbitrary webpage by a bookmarklet. It points to <code>http://localhost:5000/test</code>, which is a simple HTML page that runs the following Javascript:</p>
  
  <pre><code>$.ajax({
    type: "POST",
    url: "http://localhost:5000/parse",
    data: {data:"hello world"}
  }).done(function( msg ) {
    console.log("Success!!", arguments);
  }).fail(function(jqXHR, textStatus, errorThrown) {
    console.log("Error", arguments);
  });
  </code></pre>
  
  <p>I can see in the web inspector that the call is made, but it sits as <em>(pending)</em> until the request times out 30 seconds later. The server logs show that the server isn't being hit at all. The odd thing is that if I remove the <em>data</em> parameter in the ajax request, the server gets hit and things work as expected.</p>
  
  <pre><code>$.ajax({
    type: "POST",
    url: "http://localhost:5000/parse"
  }).done(function( msg ) {
    console.log("Success!!", arguments); // this works.
  });
  </code></pre>
  
  <p>I wouldn't expect cross-domain policy issues to be an issue since the iframe and the ajax request target are on the same domain. What am I missing here? Is there something at the browser level that is preventing this request from going through?</p>