title: PHP - Strings - Remove a HTML tag with a specific class, including its contents
body: <p>I have a string like this:</p>
  
  <pre><code>&lt;div class="container"&gt;
    &lt;h3 class="hdr"&gt; Text &lt;/h3&gt;
    &lt;div class="main"&gt;
      text
      &lt;h3&gt; text... &lt;/h3&gt;
      ....
  
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>how do I remove the H3 tag with the .hdr class using as little code as possible ?</p>