Пример прототипа в js Битрикс

<script>
    $(function(){
        if(!Firstbit)
            Firstbit = {};

        if(!Firstbit.Project)
            Firstbit.Project = {};

        Firstbit.Project.ChangePassword = function(){
            this.form = $('#<?= $arResult["FORM_ID"] ?>');
            this.wrap = 'div[data-cid="' + this.fieldName + '"]';
        };

        Firstbit.Project.ChangePassword.prototype.init = function(){
            this.events();
        };

        Firstbit.Project.ChangePassword.prototype.events = function(){
            var self = this;

            var errors = false,
                message = 0;
            $(document).on('submit', self.form, function() {
                if (!$('#modal-window [name=USER_PASSWORD]').val()) {
                    $('#modal-window [name=USER_PASSWORD]').addClass('_error').focus(function() {$(this).removeClass('_error');});
                    errors = true;
                }
                if (!$('#modal-window [name=USER_PASSWORD_NEW]').val()) {
                    $('#modal-window [name=USER_PASSWORD_NEW]').addClass('_error').focus(function() {$(this).removeClass('_error');});
                    errors = true;
                }
                if (!$('#modal-window [name=USER_PASSWORD_NEW_CONFIRM]').val()) {
                    $('#modal-window [name=USER_PASSWORD_NEW_CONFIRM]').addClass('_error').focus(function() {$(this).removeClass('_error');});
                    errors = true;
                }
                if ($('#modal-window [name=USER_PASSWORD_NEW_CONFIRM]').val() != $('#modal-window [name=USER_PASSWORD_NEW]').val()) {
                    $('#modal-window [name=USER_PASSWORD_NEW]').addClass('_error').focus(function() {$(this).removeClass('_error');});
                    $('#modal-window [name=USER_PASSWORD_NEW_CONFIRM]').addClass('_error').focus(function() {$(this).removeClass('_error');});
                    errors = true;
                }
                if (!errors) {
                    $.post(self.form.attr('action'), self.form.serialize(), function (res) {
                        var response = res.data;
                        console.log(response);
                        if (response && response.STATUS) {
                            if (response.MESSAGES !== false ) {
                                message = response.MESSAGES.length;
                            }
                            if (response.STATUS == 'OK') {
                                window.location = window.location;
                            }
                            else {
                                if (response.STATUS == 'ERROR' && message > 0) {
                                    $('#modal-window .form__errors-wrapper').empty().append('<div class="form__errors-container"></div>');
                                    while (message--) {
                                        $('#modal-window .form__errors-container').append('<span>' + response.MESSAGES[message] + '</span>');
                                        notificationOpen('message', {'message': response.MESSAGES[message]}, 10000);
                                    }
                                }
                            }
                        }
                    }, 'json');
                }
                errors = false;
                return false;
            });
        };

        var calculator = new Firstbit.Project.ChangePassword();
        calculator.init();
    });
</script>