This is how I managed to facilitate keyboard events in multiple browsers

keyup_event.js

// <input id="my-input-element" type="text" value="foo"/>
var evt, node = document.getElementById('my-input-element');

// Have to use dispatchEvent/fireEvent because jQuery.trigger will not
// fire an event attached via addEventListener. Each environment has an
// unusual way to trigger a keyup event.
if (node.dispatchEvent) {
  // Sane browsers
  try {
    // Chrome, Safari, Firefox
    evt = new KeyboardEvent('keyup');
  } catch (e) {
    // PhantomJS (wat!)
    evt = document.createEvent('KeyboardEvent');
    evt.initEvent('keyup', true, false);
  }
  evt.keyCode = 32;
  node.dispatchEvent(evt);
} else {
  // IE 8
  evt = document.createEventObject('KeyboardEvent');
  evt.keyCode = 32;
  node.fireEvent('onkeyup', evt);
}