title: onkeydown and onkeyup events don't work on Internet Explorer 8
body: <p>My code works without problems on IE9/IE10, FF, Chrome and opera but on older Internet Explorer no Keyboard input is handled.</p>
  
  <p>I have the following code for handling events. It should only fire when a new button is pressed. </p>
  
  <pre><code>lastEvent = void 0;
  
  heldKeys = {};
  
  window.onkeydown = function(event) {
  if (lastEvent &amp;&amp; lastEvent.keyCode === event.keyCode) {
    return;
  }
  lastEvent = event;
  heldKeys[event.keyCode] = true;
  switch (event.which) {
    case 80:
      return myamp.userInput("positiv");
    case 81:
      return myamp.userInput("negativ");
  }
  };
  
  window.onkeyup = function(event) {
    lastEvent = null;
    return delete heldKeys[event.keyCode];
  };
  </code></pre>