balancing Server side and Client side code on a large website

Question

Let's suppose I am programming Facebook (which i'm not), or some other site that involves heavy traffic. Our general Layout is: All CSS is in external files 99% of JS is in external files the back bone of the websites HTML is generated by a PHP/MySQL backend, then we have JS functions to generate the DOM of parts that commonly change. Our server has an inplace API that returns JSON objects that are fed to our DOM builders (JS functions), which take an JSON object array of lets say, a list of friends, then generated ALL the html used for displaying a list of friends, or events, etc. Is this reasonable? Is it common practice to have dedicated JS functions to build the DOM as I have mentioned? Is this scalable? Is JS too slow? (btw, we use JQuery almost exclusively) I know that it tremendously lowers bandwidth and server load, as the server is no longer iterating through a list of friends (of which it also queried for via MySQL) and generating all the HTML, but instead making a query and returning a small JSON object. which seems ok to me, but I would like a 2nd/3rd/4th/... opinion. Thanks alot! Let me know if I am missing any critical information.

Answer 1

Given that JS engines are being constantly developed towards improved performance, I think it's a pretty good design. We will be seeing it more and more often as HTML5 & Co gains popularity.

Answer 2

This is the approach I'm moving towards. I'm pretty happy with it. JS is certainly not too slow. You'll want a good JS templating system. Trimpath JS Templates is my favorite of those I've tried.