title: Multilevel option in select HTML
body: <p>I am currently developing a website and I have a problem.
  I want to make a list with several levels (hierarchical), except that apparently it doesn't exist (if yes tell me).
  So I made myself a system with invisible characters, the problem is that once selected, the tabs remain and it prevents to see correctly what is written. Do you have a solution?</p>
  
  <p>Thank you in advance!</p>
  
  <p>The problem : <a href="https://i.stack.imgur.com/mhl1w.png" rel="nofollow noreferrer">enter image description here</a></p>
  
  <p>The list when open : <a href="https://i.stack.imgur.com/gSaKh.png" rel="nofollow noreferrer">enter image description here</a></p>
  
  <p>The code : </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;select name="selectEmp" id="selectEmp" class="form-control selectEmp"&gt;
              &lt;option value=""&gt;&lt;/option&gt;
              &lt;option value="00.00.00" disabled="disabled"&gt;00.00.00 - Total&lt;/option&gt;
              &lt;option value="10.00.00" disabled="disabled"&gt;10.00.00 - Bâtiment 1&lt;/option&gt;
              &lt;option value="10.10.00" disabled="disabled"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;10.10.00 - Cave&lt;/option&gt;
              &lt;option selected="selected" value="10.10.10"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;10.10.10 - Test&lt;/option&gt;
              &lt;option value="10.20.00" disabled="disabled"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;10.20.00 - Niveau 1&lt;/option&gt;
              &lt;option value="10.30.00" disabled="disabled"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;10.30.00 - Niveau 2&lt;/option&gt;
              &lt;option value="20.00.00" disabled="disabled"&gt;20.00.00 - Bâtiment 2&lt;/option&gt;
              &lt;option value="20.10.00" disabled="disabled"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;20.10.00 - Cave&lt;/option&gt;
              &lt;option value="20.20.00" disabled="disabled"&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;20.20.00 - Niveau 1&lt;/option&gt;
          &lt;/select&gt;</code></pre>
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  </div>
  </p>