Using Google’s CDN to load JavaScript libraries

For rich Ajax web applications page loading time suffers from loading JavaScript libraries such as JQuery, MooTools, Prototype etc.. Most of them are larger than 50KB in size and if you are in need to combine libraries then you are adding 100KB+ to your page loads.

Also your web server will experience delivery of your own hosted JavaScript libraries across distinct geographical requests. You can easily offload your server for those files.

Assuming all possible ways to improve JavaScript libraries loading time, Google’s CDN aka Google Libraries API can be a good solution.

Why Google CDN? Why not my own server?

The Google Libraries API is a content distribution network and loading architecture for the most popular, open-source JavaScript libraries.
Google’s huge CDN (content delivery network) can deliver the file much. Since Google has large data centers all over the world, these files will be served from data centers geographically closer to your users. This helps to reduce network latency and add to reliability, scalability and so on.
The more sites that include Google’s google.load() API the greater the chance that a user has already has the file cached, thus enabling your site to load faster as the script will not need to be downloaded.
You save bandwidth as you no longer have to serve the file(s).
The versioning system that Google has created makes it effortless to include specific versions of these libraries.

All you need to do is make a Google’s Libraries API call google.load() like:


<script src="http://www.google.com/jsapi" type="text/javascript"></script>

google.load("chrome-frame", "1.0.2");
google.load("dojo", "1.5");
google.load("ext-core", "3.1.0");
google.load("jquery", "1.4.2");
google.load("jqueryui", "1.8.4");
google.load("mootools", "1.2.4");
google.load("prototype", "1.6.1.0");
google.load("scriptaculous", "1.8.3");
google.load("swfobject", "2.2");
google.load("yui", "2.8.1");
google.load("webfont", "1.0.6");

Minor Drawbacks

You’re dependent on the CDN infrastructure. If they are down, your website will be hardly usable, too. But that case u have to write extra codes to check the desired library loaded or not.