title: Replace all chars with #, except for last 4
body: <pre><code>function maskify(cc) {
      var dd = cc.toString();
      var hash = dd.replace((/./g), '#');
      for (var i = (hash.length - 4); i &lt; hash.length; i++) {
          hash[i] = dd[i];
      }
      return hash;
  }
  </code></pre>
  
  <p>I am trying to replace all chars with <code>#</code> except for last 4. Why isn't it working?</p>