Question : I am trying to validate a credit card number on a cfform

Answer : I am trying to validate a credit card number on a cfform

Especiailly with something like credit card numbers you should also validate server side - not just in javascript.

Here is what I use :









      
            Variable#" = false>
      
      
            
            
            
            
                  
                        tNumber) EQ 13) OR (Len(ATTRIBUTES.AccountNumber) EQ 16))>
                              
                        
                              
                        
                  
                  
                        er) NEQ 16>
                              
                        
                              
                        
                  
                  
                        er) NEQ 15>
                              
                        
                              
                        
                  
                  
                        er) NEQ 16>
                              
                        
                              
                        
                  
                  
                        
                  
            
            
            
                  
                        checkSumTotal = 0;
                        digitSum = 0;
                        multiplier = 1;
                        for (digitCounter = #Len(ATTRIBUTES.AccountNumber)#; digitCounter GT 0; digitCounter = digitCounter - 1)
                        {
                              // get digit and double if necessary
                              digitSum = multiplier * Val(Mid(#ATTRIBUTES.AccountNumber#, digitCounter, 1));
                              // mathematic trick to get sum of the two digits if number is 10, 12, 14, 16, or 18
                              if (digitSum GT 9)
                              {
                                    digitSum = digitSum - 9;
                              }
                              // add current digit totals to checkSum Total
                              checkSumTotal = checkSumTotal + digitSum;
                              // set multiplier for next digit (i.e. mathematic trick to flip between 2 and 1)
                              multiplier = 3 - multiplier;
                        }
                        // mark the card as invalid if it did not pass the Luhn Mod-10 Test
                        if ((checkSumTotal mod 10) NEQ 0)
                        {
                              ValidCard = false;
                        }
                  
            
            Variable#" = ValidCard>
      
      
            
      



I removed the other account types we also allow (we have other account types besides Credit card numbers like Departmental Accounts, etc.  Account types are 3 digit numbers and we make sure that the account type for credit cards start with a 0.

For example:

Visa : 001
Mastercard : 002
American Express : 003
Discover: 004

Departmental Accounts : 200

Note this is not the account number - just the account type.

You could easily add other types to the above such as Corporate accounts, student accounts, etc. just by adding a new case to the switch....