payform

A general purpose library for building credit card forms, validating inputs, and formatting numbers.

Supported card types:

• Visa
• MasterCard
• American Express
• Diners Club
• Discover
• UnionPay
• JCB
• Visa Electron
• Maestro
• Forbrugsforeningen
• Dankort

(Custom card types are also supported)

Works in IE8+ and all other modern browsers.

Demo

Installation / Usage

npm (Node and Browserify)

npm install payform --save

var payform = require('payform');

// Validate a credit card number
payform.validateCardNumber('4242 4242 4242 4242'); //=> true

// Get card type from number
payform.parseCardType('4242 4242 4242 4242'); //=> 'visa'

AMD / Require.js

require.config({
    paths: { "payform": "path/to/payform" }
});

require(["payform"], function (payform) {
  // Validate a credit card number
  payform.validateCardNumber('4242 4242 4242 4242'); //=> true

  // Get card type from number
  payform.parseCardType('4242 4242 4242 4242'); //=> 'visa'
});

Direct script include / Bower

Optionally via bower (or simply via download)

bower install payform --save

<script src="path/to/payform/dist/payform.js"></script>
<script>
  // Validate a credit card number
  payform.validateCardNumber('4242 4242 4242 4242'); //=> true

  // Get card type from number
  payform.parseCardType('4242 4242 4242 4242'); //=> 'visa'
</script>

API

General Formatting and Validation

payform.validateCardNumber(number)

Validates a card number:

• Validates numbers
• Validates Luhn algorithm
• Validates length

Example:

payform.validateCardNumber('4242 4242 4242 4242'); //=> true

payform.validateCardExpiry(month, year)

Validates a card expiry:

• Validates numbers
• Validates in the future
• Supports year shorthand

Example:

payform.validateCardExpiry('05', '20'); //=> true
payform.validateCardExpiry('05', '2015'); //=> true
payform.validateCardExpiry('05', '05'); //=> false

payform.validateCardCVC(cvc, type)

Validates a card CVC:

• Validates number
• Validates length to 4

Example:

payform.validateCardCVC('123'); //=> true
payform.validateCardCVC('123', 'amex'); //=> true
payform.validateCardCVC('1234', 'amex'); //=> true
payform.validateCardCVC('12344'); //=> false

payform.parseCardType(number)

Returns a card type. Either:

• visa
• mastercard
• amex
• dinersclub
• discover
• unionpay
• jcb
• visaelectron
• maestro
• forbrugsforeningen
• dankort

The function will return null if the card type can't be determined.

Example:

payform.parseCardType('4242 4242 4242 4242'); //=> 'visa'
payform.parseCardType('hello world?'); //=> null

payform.parseCardExpiry(string)

Parses a credit card expiry in the form of MM/YYYY, returning an object containing the month and year. Shorthand years, such as 13 are also supported (and converted into the longhand, e.g. 2013).

payform.parseCardExpiry('03 / 2025'); //=> {month: 3: year: 2025}
payform.parseCardExpiry('05 / 04'); //=> {month: 5, year: 2004}

This function doesn't perform any validation of the month or year; use payform.validateCardExpiry(month, year) for that.

Browser <input> formatting helpers

These methods are specifically for use in the browser to attach <input> formatters.

payform.cardNumberInput(input)

Formats card numbers:

• Includes a space between every 4 digits
• Restricts input to numbers
• Limits to 16 numbers
• Supports American Express formatting

Example:

var input = document.getElementById('ccnum');
payform.cardNumberInput(input);

payform.expiryInput(input)

Formats card expiry:

• Includes a / between the month and year
• Restricts input to numbers
• Restricts length

Example:

var input = document.getElementById('expiry');
payform.expiryInput(input);

payform.cvcInput(input)

Formats card CVC:

• Restricts length to 4 numbers
• Restricts input to numbers

Example:

var input = document.getElementById('cvc');
payform.cvcInput(input);

Custom Cards

payform.cards

Array of objects that describe valid card types. Each object should contain the following fields:

{
  // Card type, as returned by payform.parseCardType.
  type: 'mastercard',
  // Regex used to identify the card type. For the best experience, this should be
  // the shortest pattern that can guarantee the card is of a particular type.
  pattern: /^5[0-5]/,
  // Array of valid card number lengths.
  length: [16],
  // Array of valid card CVC lengths.
  cvcLength: [3],
  // Boolean indicating whether a valid card number should satisfy the Luhn check.
  luhn: true,
  // Regex used to format the card number. Each match is joined with a space.
  format: /(\d{1,4})/g
}

When identifying a card type, the array is traversed in order until the card number matches a pattern. For this reason, patterns with higher specificity should appear towards the beginning of the array.

Development

Please see CONTRIBUTING.md.

Autocomplete recommendations

We recommend you turn autocomplete on for credit card forms, except for the CVC field (which should never be stored). You can do this by setting the autocomplete attribute:

<form autocomplete="on">
  <input class="cc-number">
  <input class="cc-cvc" autocomplete="off">
</form>

You should also mark up your fields using the Autofill spec. These are respected by a number of browsers, including Chrome.

<input type="tel" class="cc-number" autocomplete="cc-number">

Set autocomplete to cc-number for credit card numbers and cc-exp for credit card expiry.

Mobile recommendations

We recommend you to use <input type="tel"> which will cause the numeric keyboard to be displayed on mobile devices:

<input type="tel" class="cc-number">

A derived work

This library is derived from a lot of great work done on jquery.payment by the folks at Stripe. This aims to build upon that work, in a module that can be consumed in more diverse situations.