text: (function ($) {
      $.fn.bootstrapValidator.i18n.issn = $.extend($.fn.bootstrapValidator.i18n.issn || {}, {
          'default': 'Please enter a valid ISSN number'
      });
  
      $.fn.bootstrapValidator.validators.issn = {
          /**
           * Validate ISSN (International Standard Serial Number)
           * Examples:
           * - Valid: 0378-5955, 0024-9319, 0032-1478
           * - Invalid: 0032-147X
           *
           * @see http://en.wikipedia.org/wiki/International_Standard_Serial_Number
           * @param {BootstrapValidator} validator The validator plugin instance
           * @param {jQuery} $field Field element
           * @param {Object} options Can consist of the following keys:
           * - message: The invalid message
           * @returns {Boolean}
           */
          validate: function (validator, $field, options) {
              var value = $field.val();
              if (value === '') {
                  return true;
              }
  
              // Groups are separated by a hyphen or a space
              if (!/^\d{4}\-\d{3}[\dX]$/.test(value)) {
                  return false;
              }
  
              // Replace all special characters except digits and X
              value = value.replace(/[^0-9X]/gi, '');
              var chars = value.split(''),
                  length = chars.length,
                  sum = 0;
  
              if (chars[7] === 'X') {
                  chars[7] = 10;
              }
              for (var i = 0; i < length; i++) {
                  sum += parseInt(chars[i], 10) * (8 - i);
              }
              return (sum % 11 === 0);
          }
      };
  }(window.jQuery));
  