(In a grumpy old man's voice) Back in my day, we rendered all the pages on the server, and we liked it! LOL! Times are changing and we are seeing a massive ground swell in client-side templating frameworks. At their heart, they're pretty much all the same in that they take JSON data and apply an HTML-based template contained within a script tag.
If you know what JSON is, skip this paragraph. I spent a little time last chapter discussing this, but just in case you skipped ahead and don't know, JSON is JavaScript written in such a way that it can be used as a data exchange format. It's more efficient than XML and is instantly interpretable by the browser in an object-oriented fashion. JSON can request data even across domains using JSONP. For more on JSON, read http://en.wikipedia.org/wiki/JSON. For more on JSONP, read http://en.wikipedia.org/wiki/JSONP.
All these client-side libraries have some sort of notation in them to show where the data goes and gives ways to implement...