四种asp 电子邮箱验证函数

Public Function IsEmail(ByVal PString)
Dim Plt,Pgt : Plt = False : Pgt = False
For x = 2 To Len(PString) - 1
If Mid(PString,x,1) = "@" Then Plt = True
If Mid(PString,x,1) = "." And Plt = True Then Pgt = True
Next
If Plt = True And Pgt = True Then
IsEmail = True
Else
IsEmail = False
End if
End Function
%>

'********************************************
'函数名：IsValidEmail
'作 用：检查Email地址合法性
'参 数：email ----要检查的Email地址
'返回值：True ----Email地址合法
' False ----Email地址不合法
'********************************************

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

<%
Function isemail(strng)
isemail = false
Dim regEx, Match
Set regEx = New RegExp
regEx.Pattern = "^w+((-w+)|(.w+))*@[A-Za-z0-9]+((.|-)[A-Za-z0-9]+)*.[A-Za-z0-9]+$"
regEx.IgnoreCase = True
Set Match = regEx.Execute(strng)
if match.count then isemail= true
End Function
%>

Public Function ChkMail(ByVal Email)
Dim Rep,Pmail : ChkMail = True : Set Rep = New RegExp
Rep.Pattern = "([.a-zA-Z0-9_-]){2,10}@([a-zA-Z0-9_-]){2,10}(.([a-zA-Z0-9]){2,}){1,4}$"
Pmail = Rep.Test(Email) : Set Rep = Nothing
If Not Pmail Then ChkMail = False
End Function