title: const handler = function (event) = SCRIPT1002: Syntax error (IE10)
body: <p>We're boggling our ind over a syntax error that obstructs a <a href="http://pastebin.com/BL0WnnxA" rel="nofollow">calculating script</a> in IE10 and below. It traditionally works fine in every other browser.</p>
  
  <p>The error says:</p>
  
  <pre><code>SCRIPT1002: Syntax error (line 11, char 12)
  const handler = function (event) {
  </code></pre>
  
  <p>Anyone has an idea where things get wrong please?</p>