title: Crockford - Chapter 7 - parse_url
body: <pre><code>var parse_url = /^(?:([A-Za-z]+):)?(\/{0,3})([0-9.\-A-Za-z]+)(?::(\d+))?(?:\/([^?#]*))?(?:\?([^#]*))?(?:#(.*))?$/;
  </code></pre>
  
  <p>Why is the dot . in this part 
      [0-9.-A-Za-z]+
  not escaped by a backslash?</p>