Option Explicit
Dim buffer1( 1  To  10000 ) As String
Dim buffer2( 1  To  10000 ) As String
Dim i As Integer
Dim i0 As Integer
Dim f As Integer
Dim schetchik As Integer
Dim HTML_code As Variant

Private Sub Form_Load()
i =  0 
schetchik =  1 
i0 =  0 
End Sub

Private Sub Command1_Click()
    Open app.path &"\test1.html" For Input As # 1 
    Open app.path & "\test2.html" For Input As # 2 
        If LOF( 1 ) <> LOF( 2 ) Then
        Do While Not EOF( 1 )
        i = i +  1 
            Line Input # 1 , buffer1(i)
         Loop
    Close # 1 
    
        Do While Not EOF( 2 )
        i0 = i0 +  1 
            Line Input # 2 , buffer2(i0)
        Loop
    Close # 2 
    Else
       Exit Sub
    End If
        For f =  1  To i0
                Call proverka
        Next f
End Sub

Private Sub proverka()
             If buffer1(schetchik) <> buffer2(f) Then
            Open App.Path & "\test3.html" For Append As # 3 
                Print # 3 , buffer2(f)
            Close # 3 
                schetchik = schetchik
            ElseIf buffer1(f) = buffer2(f) Then
                schetchik = schetchik +  1 
            End If
End Sub