title: How to properly write a DFP out of page ad unit?
body: <p>I am developing a javascript-rendered mobile web interstitial. The layout is fully responsive, hence it will take 100% of the provided screen\iframe.</p>
  
  <p>I now wish to display the interstitial through DFP. </p>
  
  <p>At first I created a sized ad unit (320x480) and it worked just fine, but the interstitial was limited to the boundaries of the iframe.</p>
  
  <p>I founf a new line item type called <strong>Out-of-page</strong>. The documentation states that:</p>
  
  <blockquote>
    <p>They may include pop-ups and <em>floating line items and are sometimes called interstitials.</em></p>
  </blockquote>
  
  <p><strong>But when I try to embed the interstitial in a test site, what happens is that the iframe stays 1x1, making the interstitial invisible</strong> (if I manually enlarge it with a debugger, I see it)</p>
  
  <hr>
  
  <p>My settings:</p>
  
  <ul>
  <li><strong>line item</strong> with inventory sizes of 1x1 and out of page</li>
  <li><strong>creative</strong> with my code snippet</li>
  <li><strong>ad unit</strong> is defined as size 1x1 </li>
  </ul>
  
  <hr>
  
  <p>I read in the <a href="https://support.google.com/dfp_sb/answer/3370474?hl=en" rel="noreferrer">documentation</a> that: </p>
  
  <blockquote>
    <p>If you're using a DoubleClick tag creative, you must ensure that the
    creative code trafficked on the other end of the DoubleClick tag
    (i.e., another DFP network) is properly coded for an out-of-page ad
    unit.</p>
  </blockquote>
  
  <p>What does it mean, in terms of DFP Out-of-page interstitial, that the ad is "properly coded"? How do I force the interstitial to take all the size of the screen?</p>