function startWatchingForValueChange(target, targetID) {
  activeElement = target;
  activeElementID = targetID;
  activeElementValue = target.value;
  activeElementValueProp = Object.getOwnPropertyDescriptor(target.constructor.prototype, 'value');

  // Not guarded in a canDefineProperty check: IE8 supports defineProperty only
  // on DOM elements
  Object.defineProperty(activeElement, 'value', newValueProp);
  activeElement.attachEvent('onpropertychange', handlePropertyChange);
}
(For old IE.) Starts tracking propertychange events on the passed-in element
and override the value property so that we can distinguish user events from
value changes in JS.