Pass json data into javascript

Hello from a Ruby on Rails beginner!

I’ve been trying to pass some data to a variable in Javascript by using
json. Seems like the Javascript variable doesn’t receive the data
correctly.

This is the code in controller. @courses variable find the data from
database.

class CoursesController < ApplicationController

def index
@courses = Course.find(:all)
end
end

This is Javascript code in view.

The following code show the data in browser with no problem. That means

<%= @courses.to_json %>

But the following code doesn’t show data in browser right. The output is
a string of “undefined”.

I don’t know what goes wrong. Please help. Thank you in advance.