/* Copyright NetCore 1997-2008. Licensed to Ash Alom. ashalom [AT] gmail [DOT-COM]
*********************************************************************************/


function ValidateCreditCard(s) {
  var i, n, c, r, t;

  // First, reverse the string and remove any non-numeric characters.
  r = "";
  for (i = 0; i < s.length; i++) {
    c = parseInt(s.charAt(i), 10);
    if (c >= 0 && c <= 9)
      r = c + r;
  }

  // Check for a bad string.
  if (r.length <= 1)
    return false;

  // Now run through each single digit to create a new string. Even digits
  // are multiplied by two, odd digits are left alone.
  t = "";
  for (i = 0; i < r.length; i++) {
    c = parseInt(r.charAt(i), 10);
    if (i % 2 != 0)
      c *= 2;
    t = t + c;
  }

  // Finally, add up all the single digits in this string.
  n = 0;
  for (i = 0; i < t.length; i++) {
    c = parseInt(t.charAt(i), 10);
    n = n + c;
  }

  // If the resulting sum is an even multiple of ten (but not zero), the
  // card number is good.
  if (n != 0 && n % 10 == 0)
    return true;
  else
    return false;
}