title: Cookie not being sent in iframe in IE9
body: <p>First of all, I've did some research before posting this question, so I know about <a href="https://stackoverflow.com/questions/389456/cookie-blocked-not-saved-in-iframe-in-internet-explorer">the P3P Policy</a> and <a href="http://msdn.microsoft.com/en-us/library/ms537343%28VS.85%29.aspx#unsatisfactory_cookies" rel="nofollow noreferrer">the MSDN article</a> about it. From what I understand, this policy mostly (if not only) applies to IE6. My specific problem is with IE9. Furthermore the first thing I did was set up a policy (and it works, as it shows a summary in IE's privacy report).</p>
  
  <p>My test case is as follows: I have a page that contains an iframe. The iframe document sets a session cookie (the complete HTTP header: <code>Set-Cookie:sid=2b5540e0e4f27075ca4709851700137d; expires=Tue, 28-Jun-2011 07:27:41 GMT; path=/</code>), for the current domain, on the root path, that expires in a week. No problems there, this has been running in production (standalone, not in an iframe) for some time now. </p>
  
  <p>The problem is this: the iframe document has some javascript that does some HTTP requests first (done by jQuery), then redirects the user (by changing the <code>document.location</code> property). The requests <strong>do</strong> send the cookies, but the redirect <strong>doesn't</strong>.</p>
  
  <p>I've captured the network events in IE, and the only difference between the two type of requests that I can find, is the initiator: XHR is done by a JS Library, the other by click. However I really doubt that a click would not send the cookie.</p>
  
  <p>I want to know why my cookies are not sent, the Google Analytics cookies are sent, so it should be possible.</p>
  
  <p><strong>UPDATE:</strong>
  It's definitely a privacy zone issue: when lowering the privacy bar setting in IE to all, it works. Every other setting fails.</p>
  
  <p>I've created <a href="http://jsfiddle.net/uuU46/1/embedded/result/" rel="nofollow noreferrer">an exact test bed</a>: This is the actual iframe that's being used. To test it, you have to fill in a Dutch postalcode (sorry ;)), the placeholder being used is fine: 1234 AB and 1. After submitting you get a modal, when it's done you should be redirected to a result page. In IE, the redirect shows exactly the same page that you started with (because of not setting the cookie).</p>