HTML code for tree-structured data

sample.html

<ul>
  <li><button type="button">-</button> /home <button type="button">select</button>
    <ul>
      <li><button type="button">-</button> /home/michel <button type="button">select</button>
        <ul>
          <li><button type="button">+</button> /home/michel/Documents <button type="button" disabled="">selected</button></li>
          <li><button type="button">+</button> /home/michel/Pictures <button type="button">select</button></li>
        </ul>
      </li>
    </ul>
  </li>
</ul>