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

}
    }
    for (propKey in nextProps) {
      var nextProp = nextProps[propKey];
      var lastProp =
        propKey === STYLE ? this._previousStyleCopy :
        lastProps != null ? lastProps[propKey] : undefined;
      if (!nextProps.hasOwnProperty(propKey) ||
          nextProp === lastProp ||
          nextProp == null && lastProp == null) {
        continue;
      }
      if (propKey === STYLE) {
        if (nextProp) {
          if (__DEV__) {
            checkAndWarnForMutatedStyle(
              this._previousStyleCopy,
              this._previousStyle,
              this
            );
            this._previousStyle = nextProp;
          }
          nextProp = this._previousStyleCopy = Object.assign({}, nextProp);
        } else {
          this._previousStyleCopy = null;
        }
        if (lastProp) {
          
          for (styleName in lastProp) {
            if (lastProp.hasOwnProperty(styleName) &&