title: what this means in Javascript "typeof(arguments[0])"
body: <p>I have found this in my code, probably someone has done prior to me. 
  I am unable to get what exactly this line of code does. what will arguments[0] do here.  </p>
  
  <pre><code>        typeof(arguments[0])
  </code></pre>
  
  <p>Entire code is this:</p>
  
  <pre><code> var recommendedHeight = (typeof(arguments[0]) === "number") ? arguments[0] : null;
  </code></pre>
  
  <p>The problem is I always get <code>recommendedHeight</code> as <code>null</code>. any idea when this returns any other value ?</p>