title: evaljs returns nil even though it shouldn't?
body: <p>The following code ...</p>
  
  <p><code>splash:evaljs('document.querySelectorAll("iframe.iframe-container.js-oddset-game-iframe")[0].contentDocument.querySelectorAll("td.leftText a.eventLink").length')</code> </p>
  
  <p>... returns 8 - i.e. there are 8 nodes in the array. </p>
  
  <p>However, when I then try to return the nodeList (array) directly, the result is nil? Obviously a table should be returned since an array is returned from the javascript code.</p>
  
  <p>Is this a bug in Splash? Can't Splash handle access to elements in iframes? I have the <code>--js-cross-domain-access</code> option on too.</p>