Foundation Abide Async Unique Email Validation

email_validation.js

// from http://foundation.zurb.com/forum/posts/1899-zurb-abide-ajax-validation

 (function($) {
        $.fn.markInvalid = function(text) {
            $(this).filter(":input").each(function(i, el) {
                var input = $(el);
                var container = input.closest(".row");    
                var label = container.find(".prefix");    
                var error = container.find("small.error");

                label.attr("role", "alert").addClass("error");
                input.attr("data-invalid", "");
                input.parent().addClass("error");

                if(text)
                    error.text(text);
            });
        };
    })(jQuery)

    $(document).on("valid.fndtn.abide", "#reg_username", function(e) {
        $.ajax({
            data : {
                action : "validate.username",
                username : $(e.target).val()
            },
            success : function(data) {
                if(!data.success)
                    $(e.target).markInvalid(data.messages.join('<br>'));
            }
        })
    });