Credit Card Spaces

cc_spaces.fn.js

function cc_spaces(txt){
  // rip all non digits from string
  txt = txt.toString().replace(/[^\d]/g, '');

  format = /(\d{1,4})/g;
  // test for amex.
  if (null !== txt.match(/^3[47]/)) {
    format = /(\d{1,4})(\d{1,6})?(\d{1,5})?/;
  }
  matches = txt.match(format);
  if (null === matches) {
    return '';
  }
  return matches.join(' ');
}

// Some Tests


console.log("1234567890123456: ", cc_spaces(1234567890123456));
console.log("'1234567890123456': ", cc_spaces('1234567890123456'));
console.log("'3734567890373456': ", cc_spaces('3734567890373456'));