is_null vs ===null
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/4662588/whats-the-difference-between-is-nullvar-and-var-null">What&#39;s the difference between is_null($var) and ($var === null)?</a>  </p>
</blockquote>



<p>Is there any difference between following code:</p>

<pre><code>if(is_null($x)) { ...
</code></pre>

<p>and</p>

<pre><code>if($x===null) { ...
</code></pre>
