ASP Form Validation Function _ Application Tips

'*************************************
' Detect if it contains only English and digital
'*************************************

Function IsValidValue (Arrayn, STR)
IsValidValue = False
Dim Gname
For each gname in Arrayn
If Str = Gname Then
IsValidValue = True
Exit for
End If
Next
End Function

'*************************************
' Detect if the number is valid
'*************************************

Function Isinteger (Para)
Isinteger = False
If Not (IsNull (Para) or Trim (Para) = "" Or not IsNumeric (Para)) Then
Isinteger = True
End If
End Function

'*************************************
' User name detection
'*************************************

Function IsValidUserName (ByVal UserName)
Dim I, C
Dim vUserName
IsValidUserName = True
For i = 1 to Len (UserName)
c = LCase (Mid (UserName, I, 1))
If InStr ("$!<>?#^%@~ ' &* ();: + = '" "", C) > 0 Then
IsValidUserName = False
Exit Function
End If
Next
For each vusername in Register_username
If UserName = vUserName Then
IsValidUserName = False
Exit for
End If
Next
End Function

'*************************************
' Check if valid e-mail address
'*************************************

Function IsValidEmail (Email)
Dim names, Name, I, C
IsValidEmail = True
Names = Split (email, "@")
If UBound (names) <> 1 Then
IsValidEmail = False
Exit Function
End If
For each Name in names
If Len (Name) <= 0 Then
IsValidEmail = False
Exit Function
End If
For i = 1 to Len (Name)
c = LCase (Mid (Name, I, 1))
If InStr ("abcdefghijklmnopqrstuvwxyz_-.", c) <= 0 and not IsNumeric (c) Then
IsValidEmail = False
Exit Function
End If
Next
If Left (Name, 1) = "." Or Right (Name, 1) = "." Then
IsValidEmail = False
Exit Function
End If
Next
If InStr (Names (1), ".") <= 0 Then
IsValidEmail = False
Exit Function
End If
i = Len (names (1))-InStrRev (names (1), ".")
If I <> 2 and I <> 3 Then
IsValidEmail = False
Exit Function
End If
If InStr (email, "...") > 0 Then
IsValidEmail = False
End If
End Function