反应：聚焦检测

Question

如何检测事件 FocusOut？

FocusIn 有事件：onFocusCapture、onFocus

但我没有找到 FocusOut 的活动

render() {
    return (
        <input onFocusCapture = {this.handleFocusIn} onUNKNOWN = {this.handleFocusOut} />
    );
}