Optimizing web page loading is not a new subject, but it remains one that doesn’t get as much attention as it deserves. Web/UI developers often assume that site performance is mostly attributed to back-end operations (database interactions, processing, etc.), servers themselves (hardware and software) and other variants such as bandwidth, traffic, etc. But there are many ways to optimize client-side code in a way that will result in a noticeable improvement in site loading and performance.
Fortunately, some of these techniques are becoming more common. For example, CSS Sprites are frequently seen now days and are heavily used by Google (sample) and Yahoo (sample). The reason CSS Sprites are a good idea is because reducing the number of requests means that servers have less to process and deliver, while the browsers have fewer components to download. This point is one particularly worth noting since before Firefox version 3 and Internet Explorer version 8, most browsers supported only 2 concurrent requests per domain. (With new browsers, that number goes up to 6, but the concept is no less important.)
So, loading fewer files is good for both the server and the client. CSS Sprites allow us to cut down the number of images which need to be downloaded (and also prevent having to preload images which are initially hidden, such as rollovers), but how can this technique be applied to other page components?