title: How can I convert HTML to markdown?
body: <p>I have a website like stackoverflow. There is a textarea which people write answers. I use <a href="http://parsedown.org/" rel="noreferrer">this PHP library</a> to convert markdown. I mean I use that function to convert <code>*italic*</code> to <code>&lt;i&gt;italic&lt;/i&gt;</code>.</p>
  
  <pre><code>// include that library
  $Parsedown = new Parsedown();
  echo $Parsedown-&gt;text('*italic*'); # prints: &lt;i&gt;italic&lt;/i&gt;
  </code></pre>
  
  <p>Well All fine. It should be noted I convert that answer (to html tags, not markdown symbols) befor storing, in other word, all data in the database are containing HTML tags, not markdown symbols.</p>
  
  <p>Now I want to implement <em>Editing-System</em> for answers. Something exactly like stackoverflow. So I need to convert saved answer to markdown-style again. </p>
  
  <p>Now I want to know, how can I reconvert it? I mean I want to convert <code>&lt;i&gt;italic&lt;/i&gt;</code> to <code>*italic*</code>, How can I do that?</p>