title: Alternative way to check if a Window is a Popup
body: <p>I have a page that can be opened from either my domain or as a popup opened from a different domain. In this page, I have to check it by Javascript if it was opened as a popup or if it was directly opened by it's URL and do some stuff.</p>
  
  <p>Right now, I'm following the widely suggested approach, using the <code>window.opener</code> attribute...</p>
  
  <pre><code>if (window.opener != null)
      // It is a popup
  else
      // It's not a popup
  </code></pre>
  
  <p>... but recently I've been facing an IE issue, which isn't filling up that attribute.</p>
  
  <p>Could anyone suggest me a different approach to accomplish this? The IE issue is probably unavoidable without changing some windows configurations.</p>
  
  <p>Btw, when I say that the page is being opened as a popup, I'm talking about a <code>window.open()</code> call that opens a new window.</p>
  
  <p>Thank you in advance!</p>