@startuml
participant User
participant Browser
participant Server
User -> Browser: 输入用户名和密码
Browser -> Server: 发送登录请求(包含用户名和密码)
Server -> Server: 验证用户名和密码
alt 验证成功
Server -> Browser: 返回登录成功响应
Browser -> User: 显示登录成功界面
else 验证失败
Server -> Browser: 返回登录失败响应
Browser -> User: 显示登录失败信息
end
@enduml