title: Multiselect hierarchical dropdown
body: <p>I have following requirement :</p>
  
  <ol>
  <li><p>Display a drop down based on hierarchy (Parent child relationship). </p></li>
  <li><p>Every node should be check-able (A checkbox in every option)</p></li>
  <li><p>If we select all child nodes, then parent should be checked
      automatically or vice a versa.</p></li>
  </ol>
  
  <p>For example :
  Inside a drop-down I want something like this :</p>
  
  <pre><code>[Checkbox]Element 1
        [Checkbox]Element 1.1
        [Checkbox]Element 1.2
               [Checkbox]Element 1.2.1
               [Checkbox]Element 1.2.2
  [Checkbox]Element 2
        [Checkbox]Element 2.1
        [Checkbox]Element 2.2
               [Checkbox]Element 2.2.1
               [Checkbox]Element 2.2.2
  </code></pre>
  
  <p>Kindly suggest any solution or if there is any plugin available. The hierarchy may be even more that 4-5 levels in future.</p>
  
  <p>Thanks in advance.</p>