field limit for Jquery validator

field limit for Jquery validator

I've made validation of  password field.which will take character between 6 to 16
but this is not working.it does'nt give any validation message. 

$.validator.addMethod("password",function(value,element){
    return this.optional(element) || /^[A-Za-z0-9!@#$%^&*()_]{6,16}$/i.test(value); 
    },"Passwords are 6-16 characters");


   
        // Validate signup form
        $("#signup").validate({
                rules: {
                        email: "required email",
                        username: "required username",
                        password: "required password",

                },
               

        });