Mouse Wheel and Form Opacity

hello, i am wanting to be able to change the form's opacity up and down whenever the mouse wheel is scrolled, but only to a point. how can i do this? ^^

For mouse wheel events see this

for opacity, declare these API's

vb Code:

Option Explicit
 
Private Declare Function GetWindowLongA Lib "user32" _
(ByVal hwnd As Long, ByVal nIndex As Long) As Long
 
Private Declare Function SetWindowLongA Lib "user32" _
(ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
 
Private Declare Function SetLayeredWindowAttributes Lib "user32" _
(ByVal hwnd As Long, ByVal crey As Byte, ByVal bAlpha As Byte, _
ByVal dwFlags As Long) As Long
 
Private Const GWL_EXSTYLE = (-20)
 
Private Const WS_EX_LAYERED = &H80000
 
Private Const LWA_ALPHA = &H2&
 
Private Function Opacity(Value As Byte, Frm As Form)
 
    On Error GoTo ErrorHandler
 
    Dim MaxVal As Byte, MinVal As Byte
    
    '20 is the lowest opacity setting and 255 is the highest
    MinVal = 20: MaxVal = 255
 
    If Value > MaxVal Then Value = MaxVal
 
    If Value < MinVal Then Value = MinVal
 
    SetWindowLongA Frm.hwnd, GWL_EXSTYLE, GetWindowLongA(Frm.hwnd, GWL_EXSTYLE) _
    Or WS_EX_LAYERED
 
    SetLayeredWindowAttributes Frm.hwnd, 0, Value, LWA_ALPHA
 
ErrorHandler:     Exit Function
 
End Function
 
Public Sub MouseWheelRolled()
    'to use this event see
    'http://www.andreavb.com/tip060008.html as mentioned in the 1st line above
   
 'This will change the form "me"'s opacity to 150.
    Opacity 150, Me
End Sub

Sorry to barge in on this but how would you use mouse wheel with Browser control, or FireFox Browser control.