anchor.diff:  
   <script type="text/javascript"><!--
  -
  -$(function() {
  +'use strict';
  +$(() => {
   
     const hotkeysButton = $('#hotkeys-button');
   
  
positive.code:   }
  
  });
  
  //--></script>
  
  <button type="button"
          id="hotkeys-button">
    hotkeys
  </button>
  
negative.code: 
    const tr = (key, what) => {
      return '<tr>' +
        `<td style="text-align:right;">${key}</td>` +
        '<td>&nbsp;:&nbsp;</td>' +
        `<td>${what}</td>` +
      '</tr>';
    };
  
  