优化一下：当菜单未关闭时点击×，先关闭菜单再关闭侧边栏。
//只需要在Sidebar的关闭函数里写：
if(this.menubar.state === "hasOpen"){
this.menubar.currentOpenTarget.className = 'nav-content';
this.menubar.currentOpenTarget.style.top = 0;
this.menubar.currentOpenTarget.style.left = 35 + 'px';
this.menubar.currentOpenTarget.classList.add('menuContent-move-left');
this.menubar.state = 'allClose';
}
