title: Select and focus an already existing window
body: <p>I run an e-commerce website, and I need to get this popup working when a client submits an order. Ideally, the popop would appear when the order success page loads, but popup blockers will stop this.</p>
  
  <p>Instead, I generate the popup when the use clicks the "confirm order" button, but this obscures the 3DSecure page that the checkout redirects to before the order finishes.</p>
  
  <p>To counteract this, I create the popup when the user clicks "confirm order", but instantly refocus the main window; a pop-under if you will. My plan is to refocus this new window from the order success page.</p>
  
  <p>The issue is that I cannot find a way to get the object for an existing popup so I can run the focus on it. if I create the window using <code>window.open(url,windowName,options)</code>, is there a way I can reference that from another page? Something along the lines of <code>window.load(windowName)</code> would be ideal.</p>