<!DOCTYPE html>
<html>

  <head>
    <link data-require="bootstrap@*" data-semver="3.3.7" rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" />
    <link rel="stylesheet" href="style.css" />
    <script src="script.js"></script>
  </head>

  <body>
  <div class='table-cont' id='table-cont'>
   <table class="table table-striped">
      <thead>
        <tr>
          <th>#</th>
          <th>First Name</th>
          <th>Last Name</th>
          <th>Username</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th scope="row">1</th>
          <td>Mark</td>
          <td>Otto</td>
          <td>@mdo</td>
        </tr>
        <tr>
          <th scope="row">2</th>
          <td>Jacob</td>
          <td>Thornton</td>
          <td>@fat</td>
        </tr>
        <tr>
          <th scope="row">3</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">4</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">5</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">6</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">7</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">8</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">9</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">10</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">11</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">12</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
        <tr>
          <th scope="row">13</th>
          <td>Larry</td>
          <td>the Bird</td>
          <td>@twitter</td>
        </tr>
      </tbody>
    </table>
  </div>
  </body>

</html>
// Code goes here
'use strict'
window.onload = function(){
  var tableCont = document.querySelector('#table-cont')
  /**
   * scroll handle
   * @param {event} e -- scroll event
   */
  function scrollHandle (e){
    var scrollTop = this.scrollTop;
    this.querySelector('thead').style.transform = 'translateY(' + scrollTop + 'px)';
  }
  
  tableCont.addEventListener('scroll',scrollHandle)
}
/* Styles go here */

.table-cont{
  /**make table can scroll**/
  max-height: 200px;
  overflow: auto;
  /** add some style**/
  /*padding: 2px;*/
  background: #ddd;
  margin: 20px 10px;
  box-shadow: 0 0 1px 3px #ddd;
}
thead{
  background-color: #ddd;
}