Posted By

welancers on 08/14/12


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javascript validation creditcard


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Easy Credit Card validation using Javascript


 / Published in: JavaScript
 

Do Credit Card validation easily using JavaScript

  1. function isValidCreditCard(type, ccnum) {
  2. if (type == "Visa") {
  3. // Visa: length 16, prefix 4, dashes optional.
  4. var re = /^4\d{3}-?\d{4}-?\d{4}-?\d{4}$/;
  5. } else if (type == "MC") {
  6. // Mastercard: length 16, prefix 51-55, dashes optional.
  7. var re = /^5[1-5]\d{2}-?\d{4}-?\d{4}-?\d{4}$/;
  8. } else if (type == "Disc") {
  9. // Discover: length 16, prefix 6011, dashes optional.
  10. var re = /^6011-?\d{4}-?\d{4}-?\d{4}$/;
  11. } else if (type == "AmEx") {
  12. // American Express: length 15, prefix 34 or 37.
  13. var re = /^3[4,7]\d{13}$/;
  14. } else if (type == "Diners") {
  15. // Diners: length 14, prefix 30, 36, or 38.
  16. var re = /^3[0,6,8]\d{12}$/;
  17. }
  18. if (!re.test(ccnum)) return false;
  19. // Remove all dashes for the checksum checks to eliminate negative numbers
  20. ccnum = ccnum.split("-").join("");
  21. // Checksum ("Mod 10")
  22. // Add even digits in even length strings or odd digits in odd length strings.
  23. var checksum = 0;
  24. for (var i=(2-(ccnum.length % 2)); i<=ccnum.length; i+=2) {
  25. checksum += parseInt(ccnum.charAt(i-1));
  26. }
  27. // Analyze odd digits in even length strings or even digits in odd length strings.
  28. for (var i=(ccnum.length % 2) + 1; i<ccnum.length; i+=2) {
  29. var digit = parseInt(ccnum.charAt(i-1)) * 2;
  30. if (digit < 10) { checksum += digit; } else { checksum += (digit-9); }
  31. }
  32. if ((checksum % 10) == 0) return true; else return false;
  33. }

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