title: Why doesn't empty string == null in JavaScript
body: <p>I understand that both empty string and null are falsy according to the ECMAScript. If both are falsy then why doesn't the following evaluate to true?</p>
  
  <pre><code>    var emptyString = '';
      if (emptyString == null) {
          console.log('emptyString == null');
      }
      else {
          console.log('emptyString does not == null'); // but why?
      }
  </code></pre>