Checks if any site/URL can be loaded or inserted within an iframe, by
- first checking if the remote page has some server X-Frame-Options header preventing this
- then if the remote page has some javascript redirecting the page to the full window or a to a dummy page, image or message
Note that allowing his own page or not to be inserted in a remote iframe has pros and cons, especially if the calling page makes that very clear and does not self attribute ownership nor copyright; new visitors after all (and for SEO aspect: search engines see perfectly that this is a different site)
