Weird JSON Javascript problem in Rails

This is Rails html-encoding your string as is default in Rails 3.

You need to mark your JSON as html_safe:

var stuff = <%= @json.to_s.html_safe %>

Note that .to_s is needed because as_json gives Hash instead of string. You could do this instead:

# in controller
@json = @nodes.to_json(:only => [:ID, :Lat, :Lon]) 

#and in view
var stuff = <%= @json.html_safe %>