asp IsValidEmail Verify email address function (email)

'********************************************
'Function name: IsValidEmail
'Function: Check the legality of the email address
'Article: email ----The email address to be checked
'Return value: True ----The Email address is legal
' False ----The email address is illegal
'********************************************
Public Function IsValidEmail(Email)
Dim names, name, I, c
IsValidEmail = True
names = Split(Email, "@")
If UBound(names) <> 1 Then IsValidEmail = False: Exit Function
For Each name In names
If Len(name) <= 0 Then IsValidEmail = False:Exit Function
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
Next
If Left(name, 1) = "." Or Right(name, 1) = "." Then IsValidEmail = False:Exit Function
Next
If InStr(names(1), ".") <= 0 Then IsValidEmail = False:Exit Function
I = Len(names(1)) - InStrRev(names(1), ".")
If I <> 2 And I <> 3 Then IsValidEmail = False:Exit Function
If InStr(Email, "..") > 0 Then IsValidEmail = False
End Function