Что за ошибка при валидации?

Question

[freecoder-ru]

Пишу валидацию для логина ..
Получаю ошибку по поводу test () , непонимаю почему ошибка о том что это нефункция .. В чём может быть проблема ?

(function(){

    $.validator.addMethod("NICKNAME", function (value) {
        var reg_ex = "^[a-z0-9_-]{3,15}$";
        return reg_ex.test(value);
    }, "Wrong nick name format , matched nicknames 1. mkyong34 2. mkyong_2002 3. mkyong-2002 4. mk3-4_yong! ");

    $.validator.addMethod("EMAIL", function (value) {
        var reg_ex = "^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$";
        return reg_ex.test(value);
    }, "Wrong email format, Matches: [e-mail] | [e-mail] | [e-mail] !");

    $.validator.addMethod("PASSWORD", function (value) {
        var reg_ex = "((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})";
        return reg_ex.test(value);
    }, "Wrong password format, matched password 1. mkyong1A@ 2. mkYOn12$! ");


    $("#login").validate({
        rules: {
            nick_name: {
                required:true,
                minlength: 5,
                NICKNAME:true
            },
            email: {
                required: true,
                EMAIL:true
            },
            password: {
                required:true,
                rangelength:[8, 12],
                number:true,
                PASSWORD:true
            }
        },
        messages : {
            nick_name: {
                required:"This field is required to be filled!",
                minlength:"The minimum length of nickname 5 characters!",
            },
            email :{
                required:"This field is required to be filled!",
            },
            password : {
                required:"This field is required to be filled!",
                rangelength:"The length of password must be 8-12 digits",
                number:"Password must be a number!",
            }
        }
    });
})();

Uncaught TypeError: reg_ex.test is not a function.  
Exception occurred when checking element nname, check the 'NICKNAME' method.