Love it or hate it, client side web-apps and JavaScript are here to stay. But fear not, Ruby programmer: JavaScript isn’t as cruddy as you think, and writing “proper” applications in the browser can even be fun—honest! However, you are wise to tread carefully. This is a new and dangerous land, where callbacks rule and you can’t just throw more servers at your performance problems.

In this talk, I’ll take you through some of the things I’ve learned over the past two years of moving a complex financial forecasting application into the browser, and hopefully prepare you for the coming apocalypse.