validateCC();


function checkCC(field) { 
    var number = $(field).value
    number = number.replace(/[^\d]/g,"");

    var msg = '';
    var success = false; 

    if (number.length > 4 ) {  
      var cards = new Array();
      cards [0] = {name: "Visa", 
                   regexp: /^4\d{12}(\d{3})?$/};
      cards [1] = {name: "Master Card", 
                   regexp: /^(5[1-5]\d{4}|677189)\d{10}$/};
      cards [2] = {name: "American Express", 
                   regexp: /^3[47]\d{13}$/};
      cards [3] = {name: "Discover", 
                   regexp: /^(6011|65\d{2})\d{12}$/};
  
      var card_type = -1;
      for (var i=0; cards.length > i; i++) {
          if (number.match(cards[i].regexp)) {
              card_type = i;
              break;
          }
      }
  
      var total_checksum = 0; 
      var ch = ""; 
      var multiplier = 1; 
      var checksum = 0; 
      
      for (i = number.length-1; i >= 0; i--) { 
          checksum = parseInt(number.charAt(i)) * multiplier; 
          if (checksum > 9) { 
              checksum = checksum - 9; 
          }
          total_checksum = total_checksum + checksum; 
          if (multiplier == 1) { multiplier = 2; } else { multiplier = 1; }
      }
      
      var bad_checksum = total_checksum % 10 != 0; 
      msg = 'Invalid';
      if (!bad_checksum && card_type >= 0) { 
          success = true; 
          msg = cards[card_type].name
          $(field).value = number.replace(/(\d{4})(\d{4})(\d{4})(\d+)/, "$1 $2 $3 $4")
      } 
    }
    return {success : success, msg : msg};
}

function validateCC() { 
  var check = checkCC('payment_profile_number');
  var msg = '';
  if (check.msg.length > 0) { 
    msg = "<span class='comment'>Your card: </span>" + check.msg + (check.success ? ", ok!" : "");
  }
  $('credit_card_validation').innerHTML = msg; 
}