undefined and null
<pre><code>undefined === null =&gt; false
undefined == null =&gt; true
</code></pre>

<ol>
<li><p>I have thought about the reason of <code>undefined == null</code> and found out only one case:</p>

<pre><code>if(document.getElementById() == null) ....
</code></pre>

<p>Is there any other reason to make (<code>undefined === null) == false</code> ?</p></li>
<li><p>Is there any other examples of use <code>===</code> - operation in javascript?</p></li>
</ol>
