Dim flag As Boolean ‘定义一个布尔变量flag，flag的值是true或者false，初始值是falseDim i As integer ‘定义一个整数变量Private Sub Form Load() ’窗体载入flag = Ture ‘flag=true，Me.TimerInterval=1000 ’设置timer的时间间隔，me是本窗体i=0 ’i=0End Sub ‘过程结束Private Sub Form_Timer() If flag=Ture And i<20 Then ’条件判断Me!ITimer.Caption=20-i ‘Caption赋值i=i+1ElseDoCmd.CloseEndIfEnd SubPrivate Sub OK_Click()'登录程序略'如果用户名和密码输入正确，则flag=FalseEnd Sub
