title: Html validation error for property attribute
body: <p>I am using few facebook social plugins and I am using the  meta header. When validating the page, the W3C validator is throwing the error -> "Error: there is no attribute "property".</p>
  
  <p>I am using the XHTML Transitional doctype - <code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt;</code></p>
  
  <p>Pls Suggest if I have to change the doctype to something else.</p>