Ruby和Javascript的模板引擎

We are building a web page with hashtag navigation. There is lots of data, which comes in as JSON and we use client-side templates (jQuery) to render it. So what are the options for reusable templates on both client-side and server-side (Ruby on rails)? Because we would like to have an option to fallback to a non-hashtag url and in this case server should render the data.We are building a web page with hashtag navigat