Check if an variable is refer to designate object in JavaScript
<p>Suppose I have an variable assign to an "video" tag, how can I check if this variable is refer to the object of "HTMLVideoElement"</p>

<pre><code>var video = document.getElementById('video')
if (video != object HTMLUnknownElement) {
//some code here
}
</code></pre>

<p>What is the code to replace with object HTMLUnknownElement above?</p>

<p>Thanks</p>
