React 0.14.7: `<option value="">empty</option>` emits empty string on change
http://jsbin.com/pisita/10/edit?html,js,console,output
React 15.0.0-rc.1`<option value="">empty</option>` emits string with value "empty" on change
http://jsbin.com/bemaze/12/edit?html,js,console,output
This is because React 15.0.0-rc.1 cuts off `value=""` from option tag

var tag = element.type;
  validateDangerousTag(tag);
  this._currentElement = element;
  this._tag = tag.toLowerCase();
  this._namespaceURI = null;
  this._renderedChildren = null;
  this._previousStyle = null;
  this._previousStyleCopy = null;
  this._hostNode = null;
  this._hostParent = null;
  this._rootNodeID = null;
  this._domID = null;
  this._hostContainerInfo = null;
  this._wrapperState = null;
  this._topLevelWrapper = null;
  this._flags = 0;
  if (__DEV__) {
    this._ancestorInfo = null;
    setContentChildForInstrumentation.call(this, null);
  }
}
ReactDOMComponent.displayName = 'ReactDOMComponent';