how to check available in client side with ajax, ruby on rails - ruby-on-rails

Question

I'm new in ruby on rails, and i'm trying to check validate with ajax in client side(NOT CHECK AFTER POST), I have succeeded in checking not null, but i don't know to check available. I tried some codes but i have this error:
NameError in Welcome#index
../welcome/index.html.erb where line #17 raised:
undefined local variable or method `name' for #<#<Class:0x3d80e28>:0x3354b58>
Extracted source (around line #17):
14: } else if (phonenumber == "" && email == ""){
15: alert("Please enter your email or phonenumber in the form");
16: return false;
17: } else if (<% #usernames.include?("#{name}")%>){
18: alert("Please change your name");
19: }
20: });
Here is my ajax in html:
<script>
$(document).ready(function() {
$("#button").click(function() {
var email = $("#email").val();
var name = $("#username").val();
var phonenumber = $("#phonenumber").val();
var pass = $("#password").val();
if (name == "") {
alert("Please enter your Name in the form");
return false;
} else if (pass == "") {
alert("Please enter your Password in the form");
return false;
} else if (phonenumber == "" && email == ""){
alert("Please enter your email or phonenumber in the form");
return false;
} else if (<% #usernames.include?("#{name}")%>){
alert("Please change your name");
}
});
});
</script>
Because i want to check username in client side, so i must call '#usernames' in controller, here is my controller:
def index
#usernames = User.find(:all, :select => "username")
#user = User.create(:username => params[:username], :password => params[:password],
:email => params[:email], :phonenumber => params[:phonenumber])
if #user
render 'index'
else
render 'index'
end
end
I know my problem is I don't have 'name' method in controller, but i want to check "name" in client side. So please help me to fix that! Or help me to try another way to check available :)
Update:
I tried to create :
var names = <%= #usernames%>
but i have this error in log:
SyntaxError: illegal character

Answer 1

Are you trying to populate all the usernames in js? Really ? Don't do it, you're in a way exposing all the usernames to people while you are trying to validate it instantly.
For client side validation you could use jquery validation plugin which could be found here which separates validation from rest of your js code.
Also to validate if a username is available to be allotted to a user, you can fire ajax when user starts typing. Additionally you can rely on model errors for uniqueness.
In your model you could write validates :username, :uniqueness => true so you don't have to change your code and rails will give you appropriate error messages.
I hope that helps.