As modern web applications do more and more on the client-side (the fact itself that we now refer to them as “web applications” as opposed to “web sites” is quite telling), there has been rising interest in client-side frameworks. There are a lot of players in this field but for applications with lots of functionality and many moving parts, two of them stand out in particular: Angular.js and Ember.js. Angular.js has already been introduced on this blog, so we're going to focus on Ember.js in this post, in which we'll build a simple Ember application to catalog your music collection. You'll be introduced to the framework's main building blocks and get a glimpse into its design principles.