JavaScript Function within a function undefined : <p>Can someone explain to me why the second function within the first function is undefined?</p>

<pre><code>var a = 1

function abc () { 
    alert(a); 
        function xyz () { 
            alert(a); 
        } 
}
</code></pre>

<p><a href="https://jsfiddle.net/kp950/yLs73cth/" rel="nofollow">https://jsfiddle.net/kp950/yLs73cth/</a></p>
