ĐỒNG HỒ ĐẾM NGƯỢC BẰNG VB

code
Option Explicit
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Sub CommandButton1_Click()
While (1)
DoEvents
Sleep (1000)
If (TextBox2.Text = 0 And TextBox1.Text = 0) Then
End
End If
If TextBox2.Text = 0 And TextBox1.Text > 0 Then
TextBox1.Text = TextBox1.Text - 1
TextBox2.Text = 59
Else
TextBox2.Text = TextBox2.Text - 1
End If
Wend
End Sub
Private Sub CommandButton2_Click()
End
End Sub