title: How to show <hr> when printing, but not when viewing on screen
body: <p>I'm trying to print a line on paper which I don't want to see on screen. This is what I do:</p>
  
  <pre><code>&lt;style media="screen" type="text/css"&gt;
  .print {
      display: none;
  }
  &lt;/style&gt;
  &lt;span class="print"&gt;&lt;hr&gt;&lt;/span&gt;
  </code></pre>
  
  <p>The ruler is displayed on screen as well as on paper. If I put anything else inside the span it isn't displayed. Any idea?</p>