title: How to get content/preview of an URL in Django?
body: <p>For my web app, I need to get a preview of URL given by the user.
  For example, in Facebook, if the user copy-paste an URL,it automatically fetches the content of the URL and displays a preview of the page.
  How does it work? Is it a feature of Ajax? I need to do it in Django.
  Any tutorials or demos?</p>