title: blocked a frame with origin from accessing a cross-origin frame Using the same domain
body: <p>Hi I am having a problem with this message.</p>
  
  <p>the url from my MAIN page is:</p>
  
  <pre><code>page1.mydomain.com/page1.html
  </code></pre>
  
  <p>this page have a Iframe to:</p>
  
  <pre><code>frame.mydomain.com/iframe.html
  </code></pre>
  
  <p>and from the main page I open a window from a another page like that:</p>
  
  <pre><code>mywindow = window.open("http://page1.mydomain.com/page3.html", 'page3', 'status=1,height=768,width=1280,scrollbars=1');
  </code></pre>
  
  <p>all the 3 pages have set the javascript:</p>
  
  <pre><code>document.domain = "mydomain.com";
  </code></pre>
  
  <p>I can interact from the main page to the iframe without a problem.
  I only have problem to access the window.open properties.</p>
  
  <p>Like:</p>
  
  <pre><code>mywindow.document.getElementById("something")
  </code></pre>
  
  <p>I got that error message.</p>
  
  <pre><code>blocked a frame with origin from accessing a cross-origin frame
  </code></pre>
  
  <p>if I try from the page3:</p>
  
  <pre><code>window.opener.document.getElementById("somethingPage1")
  </code></pre>
  
  <p>I got the same error:</p>
  
  <pre><code>blocked a frame with origin from accessing a cross-origin frame
  </code></pre>
  
  <p>Why I can interact with the iframe and can't interact with the window.open and the window.opener ?</p>