I'm using intercooler.js:

http://intercoolerjs.org/

It's kind of an crypto-javascript front end framework in that it makes AJAX a declarative, HTML-based tool, so the isomorphism is with respect to HTML and more traditional web development, rather than with respect to server side logic. There are events and a JS API to hook into to, though.

The docs lay out the isomorphism:

---

  <a href="http://intercoolerjs.org/">Get Intercooler</a>

This tells a browser:

"When a user clicks on this link, issue an HTTP GET request to 'http://intercoolerjs.org/' and load the response content into this browser window".

Intercooler builds on this simple concept:

  <a ic-post-to="/button_click">Click Me!</a>

This tells a browser:

"When a user clicks on this link, issue an HTTP POST request to '/button_click' and load the response content into this element".