title: Select and count the length of unchecked checkboxes using each()
body: <p>I only know how to check checked, have no idea how to include the ! (not).. I want to check how many checkboxes are left unchecked when a checkbox is checked.. </p>
  
  <pre><code>$('ul li input:checkbox:checked').each(function() {
        var count = 0;      
        var lenghtOfChecked = count++;
  });
  </code></pre>