根据用户登陆的不同权限，显示菜单是否可用-user landing different authority, show the menu is available

一个登陆界面有源程序。密码good用户good 3次不对就提示错误 退出程序。这些功能，给界面学习提供参考。-A source of a login screen. Good good 3 times the user password to an error not to exit the program. These features provide a reference to the interface to learn.