How can I determine whether the email address format is correct?

Method 1:

<%

Function IsValidEmail (Email)

ValidFlag = False

If (Email <> "") And (InStr (1, Email, "@")> 0) And (InStr (1, Email, ".")> 0) Then

AtCount = 0

SpecialFlag = False

For atLoop = 1 To Len (Email)

AtChr = Mid (Email, atLoop, 1)

If atChr = "@" Then atCount = atCount + 1

If (atChr> = Chr (32) And (atChr <= Chr (44) Then SpecialFlag = True

If (atChr = Chr (47) Or (atChr = Chr (96) Or (atChr> = Chr (123) Then SpecialFlag = True

If (atChr> = Chr (58) And (atChr <= Chr (63) Then SpecialFlag = True

If (atChr> = Chr (91) And (atChr <= Chr (94) Then SpecialFlag = True

Next

If (atCount = 1) And (SpecialFlag = False) Then

BadFlag = False

TAry1 = Split (Email ,"@")

UserName = tAry1 (0)

DomainName = tAry1 (1)

If (UserName = "") Or (DomainName = "") Then BadFlag = True

If Mid (DomainName, 1, 1) = "." then BadFlag = True

If Mid (DomainName, Len (DomainName), 1) = "." then BadFlag = True

ValidFlag = True

'The format is correct and true is returned.

End If

End If

If BadFlag = True Then ValidFlag = False

'If the format is incorrect, False is returned.

IsValidEmail = ValidFlag

End Function

%>

Method 2:

<%
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)-faster Rev (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
%>

The third method is to use the following function for judgment. It checks whether the email address contains "@" and whether "." Is after:

Function isEmail (pInString)

LAt = False
LDot = false

For x = 2 to len (pInstring)-1
If mid (pInString, x, 1) = "@" then lAt = True
If mid (pInString, x, 1) = "." and lAt = True then lDot = True
Next

If lAt = True and lDot = True then
IsEmail = True
Else
IsEmail = False
End if
End function

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