Why does null == undefined evaluate to true?
<p>I have a code below which is not clear to me</p>

<pre><code>var a = null; 
if(a==undefined)
alert("true");
else 
alert("false");
</code></pre>

<p>When I ran above code it alerts true.</p>

<p>Can anybody explain whats the reason or concept behind this?</p>