As far as I can tell,
property is not a valid attribute of the
<meta> tag in any of HTML 3, 4, XHTML-Transitional or XHTML-Strict. So why does the Open Graph Protocol (and Facebook's API docs) specify example code like this?
<html xmlns:og="http://ogp.me/ns#"> <head> <title>The Rock (1996)</title> <meta property="og:title" content="The Rock" /> <meta property="og:type" content="movie" /> <meta property="og:url" content="http://www.imdb.com/title/tt0117500/" /> <meta property="og:image" content="http://ia.media-imdb.com/images/rock.jpg" />
This doesn't validate. Changing
name does validate, and I can verify that, at least on Facebook, it still works as intended. So why do they use
property in their example code?