title: How to use Express JS 4.0's csurf?
body: <p>I have been checking <a href="https://github.com/expressjs/csurf">csurf</a>'s wiki, but it is empty. This module adds a <code>csrfToken()</code> function to user requests, but then, how should I use it?</p>
  
  <p>Can someone give a code example with explanations? What should I do on user side? What should I do on server-side?</p>