Bootstrap 4 + Parsley JS

form.html

  $("#parsleyForm").parsley({
    errorClass: 'has-danger',
    successClass: 'has-success',
    classHandler: function(ParsleyField) {
        return ParsleyField.$element.parents('.form-group');
    },
    errorsContainer: function(ParsleyField) {
        return ParsleyField.$element.parents('.form-group');
    },
    errorsWrapper: '<span class="text-help">',
    errorTemplate: '<div></div>'
  });