title: Regular expression to remove empty <span> tags
body: <p>I would like such empty span tags (filled with <code>&amp;nbsp;</code> and space) to be removed:</p>
  
  <p><code>&lt;span&gt; &amp;nbsp; &amp;nbsp; &amp;nbsp; &lt;/span&gt;</code></p>
  
  <p>I've tried with this regex, but it needs adjusting: </p>
  
  <p><code>(&lt;span&gt;(&amp;nbsp;|\s)*&lt;/span&gt;)</code></p>
  
  <p><code>preg_replace('#&lt;span&gt;(&amp;nbsp;|\s)*&lt;/span&gt;#si','&lt;\\1&gt;',$encoded);</code></p>