Is there a way to call the jruby function from javascript, let's say that I need my user interface to be on the browser side.
Note. I do not use Ruby on Rails
~ Eder Quiñones
Short answer
No.
Long answer
You can create a server-side application and invoke it through AJAX.
UPD
And yes: How to create a Java applet using JRuby? : D
Not directly. But you can use AJAX to send a request for ruby code on an internal server. This code can then send data to the interface module in an AJAX response (for example, like JSON).