<!doctype html>
<html>
<head>
  <meta charset="utf8" />
  <title>A jQuery Plugin to make a table sortable by clicking header cells</title>
  <style>
    table thead th {
      cursor: pointer;
    }

    table thead th.nosort {
      cursor: initial;
    }

    .table_sortable thead th:after {
        display: inline-block;
        padding: 0 .25rem;
    }

    .table_sortable thead th.desc:after {
        content: '↑';
    }

    .table_sortable thead th.asc:after {
        content: '↓';
    }
  </style>
</head>
<body>
  <table id="myTable" border="1">
      <thead>
          <tr>
              <th rowspan="2" class="nosort" title="nosort">Nr.</th>
              <th rowspan="2">Name</th>
              <th colspan="2">Order</th>
          </tr>
          <tr>
              <th>number</th>
              <th>text</th>
          </tr>
      </thead>
      <tbody>
          <tr>
              <td>1.</td>
              <td>Nikola</td>
              <td>2</td>
              <td>Tesla</td>
          </tr>
          <tr>
              <td>2.</td>
              <td>John</td>
              <td>0</td>
              <td>Miller</td>
          </tr>
          <tr>
              <td>3.</td>
              <td>Jacque</td>
              <td>1</td>
              <td>Fresco</td>
          </tr>
      </tbody>
      <tfoot>
        <tr>
          <td>-</td>
          <td><a href="https://github.com/duzun/jquery.tableSortable">GitHub</a></td>
          <td>-</td>
          <td><a href="https://www.npmjs.com/package/jquery-tablesortable">npm</a></td>
        </tr>
      </tfoot>
  </table>

  <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
  <script src="https://unpkg.com/jquery-tablesortable"></script>
  <script>$('table#myTable').tableSortable();</script>
</body>
</html>