Mod 10 Function

[jesus4u]

I found a Mod10 script that checks the numbers in a given credit card.

<%

Function IsCreditCard(ByRef asCardType, ByRef anCardNumber)

' Performs a Mod 10 check to make sure the credit card number
' appears valid
My question is this?

THe asCardType and anCardNumber are they variables that I name based on the textboxes name that contain the data on the previous form?

[buster1000]

Do you have the rest of the coding for that function, mayb it could help to check???

[jesus4u]

Sure

<%

Function IsCreditCard(ByRef lstCreditCard, ByRef txtAccountNumber)'asCardType, anCardNumber

' Performs a Mod 10 check to make sure the credit card number
' appears valid

' Developers may use the following numbers as dummy data:

' Visa: 430-00000-00000
' American Express: 372-00000-00000
' Mastercard: 521-00000-00000
' Discover: 620-00000-00000

Dim lsNumber ' Credit card number stripped of all spaces, dashes, etc.
Dim lsChar ' an individual character
Dim lnTotal ' Sum of all calculations
Dim lnDigit ' A digit found within a credit card number
Dim lnPosition ' identifies a character position in a string
Dim lnSum ' Sum of calculations for a specific set


txtReg1FirstName=request.form("txtReg1FirstName")
txtReg1LastName=request.form("txtReg1LastName")
lstReg1Type=request.form("lstReg1Type")
txtReg1Badge=request.form("txtReg1Badge")

txtFirstName=request.form("txtFirstName")
txtLastName=request.form("txtLastName")
txtAddress=request.form("txtAddress")
txtCity=request.form("txtCity")
lstState=request.form("lstState")
txtZip=request.form("txtZip")
txtPhone=request.form("txtPhone")
lstCreditCard=request.form("lstCreditCard")
txtAccountNumber=request.form("txtAccountNumber")
txtExpDate=request.form("txtExpDate")

' Default result is false
IsCreditCard = False

' ====
' Strip all characters that are not numbers.
' ====

' Loop through each character in the card number submited
For lnPosition = 1 To Len(txtAccountNumber)

' Grab the current character
lsChar = Mid(txtAccountNumber, lnPosition, 1)

' If the character is a number, append it to our new number
If IsNumeric(lsChar) Then lsNumber = lsNumber & lsChar

Next ' lnPosition

' ====
' The credit card number must be between 13 and 16 digits.
' ====

' If the length of the number is less then 13 digits, then exit the routine
If Len(lsNumber) < 13 Then
Response.Redirect "../mod10/moderror.asp"
Exit Function

' If the length of the number is more then 16 digits, then exit the routine
Else If Len(lsNumber) > 16 Then
Response.Redirect "../mod10/moderror.asp"
Exit Function

End If
End If


' ====
' The credit card number must start with:
' 4 for Visa Cards
' 37 for American Express Cards
' 5 for MasterCards
' 6 for Discover Cards
' ====

' Choose action based on type of card
Select Case LCase(asCardType)

' VISA
Case "visa", "v"

' If first digit not 4, exit function
If Not Left(lsNumber, 1) = "4" Then Exit Function

' American Express
Case "american express", "americanexpress", "american", "ax", "a"

' If first 2 digits not 37, exit function
If Not Left(lsNumber, 2) = "37" Then Exit Function

' Mastercard
Case "mastercard", "master card", "master", "m"

' If first digit not 5, exit function
If Not Left(lsNumber, 1) = "5" Then Exit Function

' Discover
Case "discover", "discovercard", "discover card", "d"

' If first digit not 6, exit function
If Not Left(lsNumber, 1) = "6" Then Exit Function

Case Else

End Select ' LCase(asCardType)

' ====
' If the credit card number is less then 16 digits add zeros
' to the beginning to make it 16 digits.
' ====

' Continue loop while the length of the number is less then 16 digits
While Not Len(lsNumber) = 16

' Insert 0 to the beginning of the number
lsNumber = "0" & lsNumber

Wend ' Not Len(lsNumber) = 16

' ====
' Multiply each digit of the credit card number by the corresponding digit of
' the mask, and sum the results together.
' ====

' Loop through each digit
For lnPosition = 1 To 16

' Parse a digit from a specified position in the number
lnDigit = Mid(lsNumber, lnPosition, 1)

' Determine if we multiply by:
' 1 (Even)
' 2 (Odd)
' based on the position that we are reading the digit from
lnMultiplier = 1 + (lnPosition Mod 2)

' Calculate the sum by multiplying the digit and the Multiplier
lnSum = lnDigit * lnMultiplier

' (Single digits roll over to remain single. We manually have to do this.)
' If the Sum is 10 or more, subtract 9
If lnSum > 9 Then lnSum = lnSum - 9

' Add the sum to the total of all sums
lnTotal = lnTotal + lnSum

Next ' lnPosition

' ====
' Once all the results are summed divide
' by 10, if there is no remainder then the credit card number is valid.
' ====

IsCreditCard = ((lnTotal Mod 10) = 0)

End Function ' IsCreditCard

%>

[buster1000]

Sorry , can you show me the part of the coding where you call up that function, cuze for sure it received 2 values coming from somewhere