Make a script to check whether webpage/website can be loaded in iFrame

Make a small, but robust, script which can tell whether a page is correctly loaded in an iFrame. [login to view URL], [login to view URL], [login to view URL], [login to view URL], [login to view URL] are examples of websites which are non-framable. Note that the script should detect these websites correctly as well as the website which are in fact framable. The script can be as simple as: [login to view URL]://[login to view URL] Returning: 1 if framable or 0 if non-framable. Please outline your rough approach and make clear why your approach is robust (i.e. that it will detect the the framability of webpages correctly). Thank you for your response and bids.