title: alert function in javaScript
body: <p>Can someone help me to better understand why the second alert box appears with 'undefined' in it? When I call the function without alert function I don't see it.</p>
  
  <pre><code>var n = 1;  // global scope
  
  function one() {
  alert(n);
  } 
  alert(one());
  </code></pre>