bootstrapvalidator/src/js/validator/choice.js

(function($) {
    $.fn.bootstrapValidator.validators.choice = {
        html5Attributes: ['min', 'max'],

        /**
         * Check if the number of checked boxes are less or more than a given number
         *
         * @param {BootstrapValidator} validator The validator plugin instance
         * @param {jQuery} $field Field element
         * @param {Object} options Consists of following keys:
         * - min
         * - max
         * At least one of two keys is required
         * @returns {Boolean}
         */
        validate: function(validator, $field, options) {
            var numChoices = validator
                                    .getFieldElements($field.attr('data-bv-field'))
                                    .filter(':checked')
                                    .length;
            if ((options.min && numChoices < options.min) || (options.max && numChoices > options.max)) {
                return false;
            }

            return true;
        }
    };
}(window.jQuery));