title: Use content of an element in attr() of pseudo-element
body: <p>I have the following text:</p>
  
  <pre><code>&lt;span class="page-number"&gt;42&lt;/span&gt;
  </code></pre>
  
  <p>And I want to create a pseudo-element with something like this:</p>
  
  <pre class="lang-css prettyprint-override"><code>span.page-number::after {
      content: attr(text());
  }
  </code></pre>
  
  <p>Such that the content of the pseudo-element is the text of the  element, in this case 42. Can I do something like that through some trickery? </p>