title: Is it safe to change to the HTML5 DOCTYPE?
body: <p>My site is currently using:</p>
  
  <pre><code>&lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"&gt;
  </code></pre>
  
  <p>However, things like Facebook plugins are only valid in HTML5. So, is it safe to change my DOCTYPE to <code>&lt;!DOCTYPE html&gt;</code>? Will this affect anything?</p>