title: Can DOMContentLoaded event not be fired in any circumstance?
body: <p>For example chained events of this kind won't work because the event will be fired only once.</p>
  
  <pre><code>window.addEventListener('DOMContentLoaded', function () {
      alert('This should show up');
      window.addEventListener('DOMContentLoaded', function () {
      alert('This will never show up');
      });
  });
  </code></pre>
  
  <p>Particularly my doubt is in the case you put your scripts at the bottom of the HTML, as they will be parsed when the DOM has already been loaded. More, if there are many things in your script before your event because the event could be fired before the parser reaches the <code>addEventListener</code> statement.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
      ...
      &lt;script src="myscript.js"&gt;&lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>And the javascript:</p>
  
  <pre><code>// myscript.js
  // ... many things ...
  window.addEventListener('DOMContentLoaded', function () {
      alert('Will this always happen?');
  });
  </code></pre>
  
  <p>I've tried this and it works, but my question is if there is any case where it wouldn't and if there is any guarantee that it will be fired at least once, also in offline.</p>