title: eval returning undefined, browser returning a result
body: <p>I've got a javascript string such as the following:</p>
  
  <pre><code>"h" + "e" + "l" + ("foo", "bar", "l") + ("abc", "def", "o")
  </code></pre>
  
  <p>If I save the string to a variable and eval it, it returns as undefined:</p>
  
  <pre><code>var str = "h" + "e" + "l" + ("foo", "bar", "l") + ("abc", "def", "o");
  var x = eval (str);
  console.log(x) // undefined
  </code></pre>
  
  <p>However, if I paste the string into the Chrome JS console, it returns as expected:</p>
  
  <pre><code>"hello"
  </code></pre>
  
  <p>Any reason why eval would return undefined, and how is the JS console accomplishing the feat?</p>
  
  <p>Thanks!</p>