PUBLIC MARKS from dzc with tag iframe

To improve the protection of web applications against clickjacking, this document describes the X-Frame-Options HTTP header field, which declares a policy, communicated from the server to the client browser, regarding whether the browser may display the transmitted content in frames that are part of other web pages.

Instead of embedding the full Youtube video player, Google+ only displays the thumbnail of a YouTube video and then overlays a play icon over the video so the image resembles a video player.