credit card validation

[Sakana]

Hi,

I have tried on doing the credit card validation however, it does not work out. What actually went wrong?

VB Script

Function ValidateCreditCard(ByVal cardName As String, _
ByVal cardNo As String, ByVal cardMonth As Integer, _
ByVal cardYear As Integer, ByVal PaymentAmt As String)

'check to ensure that the number is numeric
If Not IsNumeric(cardNo) Then
Session("errorMsg") = "Please enter a valid number for credit card."
Return 1 'If return 1, invalid credit card number

Else
ValidateCCNumber(cardNo)
Session("errorMsg") = "Please enter a valid number for credit card."
End If

Session("errorMsg") = ""
Return 0

End Function

Function ValidateCCNumber(ByVal cardNo)
Dim intCCType
intCCType = GetCCType(cardNo)
Select Case intCCType
Case 1 'Visa
'Validates Length Based on CardType If
' true actually validates number
If (Len(cardNo) = 13 Or Len(cardNo) = 16) And ValidateMod10(cardNo) = True Then
ValidateCCNumber = intCCType 'Valid
Else
ValidateCCNumber = intCCType * -1 'Invalid
End If
Case 2, 3 'Mastercard / Discover
If Len(cardNo) = 16 And ValidateMod10(cardNo) = True Then
ValidateCCNumber = intCCType 'Valid
Else
ValidateCCNumber = intCCType * -1 'Invalid
End If
Case 4 'American Express
If Len(cardNo) = 15 And ValidateMod10(cardNo) = True Then
ValidateCCNumber = intCCType 'Valid
Else
ValidateCCNumber = intCCType * -1 'Invalid
End If
Case 5 'Diners Club
If Len(cardNo) = 14 And ValidateMod10(cardNo) = True Then
ValidateCCNumber = intCCType 'Valid
Else
ValidateCCNumber = intCCType * -1 'Invalid
End If
Case Else
ValidateCCNumber = 0
Return 3
End Select
End Function


Function GetCCType(ByVal cardNo)
If Left(cardNo, 1) = 4 Then
'Visa
GetCCType = 1
ElseIf Left(cardNo, 2) >= 51 And Left(cardNo, 2) <= 55 Then
'Mastercard
GetCCType = 2
ElseIf Left(cardNo, 4) = 6011 Then
'Discover
GetCCType = 3
ElseIf Left(cardNo, 2) = 34 Or Left(cardNo, 2) = 37 Then
'American Express
GetCCType = 4
ElseIf (Left(cardNo, 3) >= 300 And Left(cardNo, 3) <= 305) Or _
Left(cardNo, 2) = 36 Or Left(cardNo, 2) = 38 Then
'Diners Club -- I don't know if this works coz i dun haf one to check it wif
GetCCType = 5
Else
GetCCType = 0
End If
End Function

'This is the actual Mod10
Private Function ValidateMod10(ByVal cardNo)
Dim intCounter, intTotal
Dim strTotal

intTotal = 0
For intCounter = 1 To Len(cardNo)
If (intCounter Mod 2) <> 0 Then
strTotal = strTotal & Mid(cardNo, intCounter, 1) * 2
Else
strTotal = strTotal & Mid(cardNo, intCounter, 1)
End If
Next

For intCounter = 1 To Len(strTotal)
intTotal = intTotal + Mid(strTotal, intCounter, 1)
Next

If (intTotal Mod 10) Then
ValidateMod10 = False
Else
ValidateMod10 = True
End If
End Function

[adeelahmed]

Hi Try using these functions for validating credit card.


<%
function isNumber(val)
if isNumeric(val.value) then
isNumber = true
else
msgbox "This value must be numeric."
val.select
isNumber = false
end if
end function

function isLength(val)
if len(val.value)>0 then
isLength = true
else
msgbox "This value can't be empty."
val.select
isLength = false
end if
end function

function isProperdate(val)
if isDate(trim(val.value)) then
isProperdate = true
else
msgbox "Please enter a valid date."
val.select
isProperdate = false
end if
end function

function isCCnumber(val)
if isLength(val) then
ccnumber = false
val.value = trim(replace(val.value," ",""))
if isNumeric(val.value) then
ccnum = val.value
for i = len(ccnum) to 2 step -2
total = total + cint(mid(ccnum,i,1))
tmp = cstr((mid(ccnum,i-1,1))*2)
total = total + cint(left(tmp, 1))
if len(tmp)>1 then
total = total + cint(right(tmp,1))
end if
next
if len(ccnum) mod 2 = 1 then
total = total + cint(left(ccnum,1))
end if
if total mod 10 = 0 then
ccnumber = true
end if
end if
if ccnumber then
isCCnumber = true
else
msgbox "Please use a valid credit card number."
val.select
isCCnumber = false
end if
end if
end function

function isCCdate(val)
if isLength(val) then
ccdate = false
if len(val.value)>=3 and len(val.value)<=5 then
if instr(val.value,"/")>0 then
tCC = split(val.value,"/")
if isNumeric(tCC(0)) and isNumeric(tCC(1)) then
mn = cint(tCC(0))
yr = cint(tCC(1))
currYear = cint(right(year(date()),2))
if mn>0 and mn<13 then
if yr = currYear then
if mn >= month(date()) then
ccdate = true
end if
else
if yr<currYear+4 then
ccdate = true
end if
end if
end if
end if
end if
end if
if ccdate then
isCCdate = true
else
msgbox "Please enter a valid expiry date."
val.select
isCCdate = false
end if
end if
end function


function isPositive(val)
if isNumber(val) then
if val.value>=0 then
isPositive = true
else
msgbox "Please enter a positive number."
val.select
isPositive = false
end if
end if
end function

function isNegative(val)
if isNumber(val) then
if val.value<0 then
isNegative = true
else
msgbox "Please enter a negative number."
val.select
isNegative = false
end if
end if
end function

function isAlpha(val)
if isLength(val) then
isNot=" !@#$^*()_+=-'`~\|]}[{;:/?.,<>&%"
invalid = false
if instr(val.value,chr(34))>0 then
invalid=true
else
for i = 1 to len(val.value)
for x = 1 to len(isNotAlpha)
if mid(val.value,i,1)=mid(isNot,x,1) then
invalid = true
end if
next
next
end if
if not invalid then
isAlpha = true
else
msgbox "Please use alphanumeric characters."
val.select
isAlpha = false
end if
end if
end function
%>

[Sakana]

Thank You!! My saviour!

Can you explain to me how this code below works as i need to confirm how it works. Thank You very much!

coding:

function isCCnumber(val)
if isLength(val) then
ccnumber = false
val.value = trim(replace(val.value," ",""))
if isNumeric(val.value) then
ccnum = val.value
for i = len(ccnum) to 2 step -2
total = total + cint(mid(ccnum,i,1))
tmp = cstr((mid(ccnum,i-1,1))*2)
total = total + cint(left(tmp, 1))
if len(tmp)>1 then
total = total + cint(right(tmp,1))
end if
next
if len(ccnum) mod 2 = 1 then
total = total + cint(left(ccnum,1))
end if
if total mod 10 = 0 then
ccnumber = true
end if
end if
if ccnumber then
isCCnumber = true
else
msgbox "Please use a valid credit card number."
val.select
isCCnumber = false
end if
end if
end function