title: stop loading iframe and redirect parent window if user has not logged in
body: <p>I have a web page, which can open a <code>Target PHP URL</code> in same domain in an IFRAME lightbox when user clicks a link. Inside the target URL, If "user logged in check" fails, how can I stop opening the IFRAME and redirect the parent window to login page?</p>
  
  <p>or rather, open the Iframe only if user has logged in. Else, redirect the parent window to login page.</p>
  
  <p>Appreciate any help.</p>