title: what are data-* HTML attributes?
body: <p>I've recently found on one of the sites opening  tag like this:</p>
  
  <p><code>&lt;script data-ip="93.1xx.3.2x" data-backuri="something.com"&gt;</code></p>
  
  <p>And I couldn't find any information about it. What are those tags used for?</p>