title: Python webdriver to handle pop up browser windows which is not an alert
body: <p>I am working on a  web application, in which clicking on some link another popup windows appears. The pop windows is not an alert but its a form with various fields to be entered by user and click "Next". </p>
  
  <p>How can I handle/automate this popup windows using selenium.</p>
  
  <p>Summary :-</p>
  
  <ol>
  <li>Click on the hyperlink (url) - "CLICK HERE"</li>
  <li>A user registration form appears as a pop up</li>
  <li>A data is to be filled by user </li>
  <li>Click Next/Submit button.</li>
  <li>Another next redirected to another page/form 'User Personal Information Page'</li>
  <li>Personal information is to be filled by user</li>
  <li>Click "Next/Submit"</li>
  <li>Popup disappeared.</li>
  <li>Now further processing on original/Base page.</li>
  </ol>