function modifierStateGetter(keyArg) {
  /*jshint validthis:true */
  var syntheticEvent = this;
  var nativeEvent = syntheticEvent.nativeEvent;
  if (nativeEvent.getModifierState) {
    return nativeEvent.getModifierState(keyArg);
  }
  var keyProp = modifierKeyToProp[keyArg];
  return keyProp ? !!nativeEvent[keyProp] : false;
}
Some browsers cannot use `innerHTML` to render certain elements standalone,
so we wrap them, render the wrapped nodes, then extract the desired node.

In IE8, certain elements cannot render alone, so wrap all elements ('*').