Google and MS duke it out over CDN for jQuery…YOU reap the benefits!

First off if you don’t know what jQuery is by now then this post probably won’t make a lot of sense to you, so in that case visit jQuery’s website and get back to me when your a web 2.0 expert.

It was just announced that Microsoft is going to host their MS Ajax javascript libraries and jQuery libraries for you on their CDN servers.  Check out Scott Gu’s post on the matter but to make a long story short, MS has “strategically” placed servers all over the world that will serve up the MS Ajax and jQuery libraries for you.  All you have to do is include your <script src=”{insert js library favorite flavor}.js”> in your HTML and have it point to the appropriate JS file on Microsoft’s CDN server(s).  Check out all the versions it supports on the Asp.Net AJAX CDN site.

This is obviously pretty cool because chances are Microsoft’s servers will have better uptime than your own so you can pretty much rely on that JS file always being there.  In addition, its free for anyone to use, commercial or non-commercial.

You may be thinking to yourself “wow, that’s so cool of Microsoft, they are really thinking of the little guy!”, which isn’t a COMPLETELY wrong statement, but did you know that Google has been doing the same thing for quite awhile now?

If you check out jQuery’s website, the jQuery authors themselves even recommend grabbing jQuery from google’s site, check out How jQuery works and look at the “Complete Example” section near the top.

Also, if your interested, have a look at Google’s page and see what other js libs they host for you (hint: jQuery, Prototype, Yahoo YUI, Dojo, script.aculo.us).

So, how do I leverage either the MS or Google CDN for my jQuery js files?  Simple! see below

Google: <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.min.js" type="text/javascript"></script>

or

MS: <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.3.2.min.js" type="text/javascript"></script>

*** If your asking yourself what is the difference between “jquery.min.js” and “jquery.js” the answer is that the “min” means that the js file is compressed meaning it has whitespace removed, making it significantly smaller resulting in less download size for your users which results in your sites faster page loads.

Great! Now your going to go and change all your <script> tags in all your projects to use either the MS or Google CDN version of jQuery, right?!?!?!?!  Now hold up there partner!! Take a step back and think about this and what it means to your app and where your app lives.

Ask yourself these questions:

Is your app on the internet?

Then I would say you should probably be using of the two CDN’s for your jQuery libraries because your app is internet facing and the js files will be served up quicker to your users and your pages will load faster.

Is your app an intranet app?

Then take a step back and think this one out logically.  What server is going to serve up the jQuery libraries faster?  Google? No!  Microsoft? No!  A server on the intranet? BINGO!  A server on your intranet more than likely serve up the js files a hell of a lot faster than a users PC having to call out to Google or MS to get the js files.  (Yes, a caching server may help matters)

For all you SharePoint junkies out there like me the two questions above are VERY relevant.  Chances are the majority of SharePoint sites your working on are going to be intranet facing sites and therefore your still better off hosting the js libraries yourself.  BUT, if your working on a SharePoint INTERNET facing site, then one of these CDN’s should be something you seriously consider because SharePoint takes long enough to load a page so any increase in page load times you can make will go a long way.

Moral of the story time.  Take a second and think to yourself before just reading a post out on the interwebs and implementing it.  Think about the effects it will have on your app and be sure to take into account YOUR environment.