<!DOCTYPE html>
<html>
<head>
  <style>
  .text {
    color: rgb(255, 255, 255);
    padding: 5px;
  }
  </style>
  <script type="text/javascript">
    function start() {
      document.addEventListener('keypress', onKeypress);
    }

    function onKeypress(event) {
      var k = String.fromCharCode(event.charCode);
      switch(k) {
        case 'c':
          try {
            throw ({'message': 'test exception'});
          } catch(e) {
            console.log('Caught exception: ' + e);
          }
          break;
        case 'd':
          debugger;
          break;
        case 'e':
          throw({'message': 'test exception'});
          break;
      }
    }

    window.addEventListener('load', start);
  </script>
</head>

<body style="background: rgb(0,0,0);">
  <div class='text'>C: throws caught exception</div>
  <div class='text'>D: executes 'debugger' statement</div>
  <div class='text'>E: throws uncaught exception</div>
</body>
</html>