Browser simulator independent of web framework for Rails?

Question

Is there any browser simulator that fulfills these requirements:

• gem written in Ruby
• automatically performing Ajax and Javascript code (XSS is not an issue in my case)
• independent of the frameworks used by the website (Rails, JavaEE, ASP.NET, ...)
• only client-side
• no testing
• no browser dependency

Comments

What do you mean 'no testing'? If not for testing then what is it for?