Microsoft CDN for jQuery or Google CDN? [closed]

Question

Does it actually matter which CDN you use to link to your jquery file or any javascript file for that matter. Is one potentially faster than the other? What other factors could play a role in which cdn you decide to use? I know that Microsoft, Yahoo, and Google all have CDN's now.

Answer 1

It probably doesn't matter, but you could validate this with some A/B testing. Send half of your traffic to one CDN, and half to the other, and set up some profiling to measure the response. I would think it more important to be able to switch easily in case one or the other had some serious unavailability issues.

Answer 2

In the summery it says that microsoft is not offering UI, that is not correct (any more). It can be downloadloade at http://www.asp.net/ajaxlibrary/cdn.ashx.

Answer 3

Is one potentially faster than the other?

I was actually curious of this myself so I setup a jsbin test page using each of the following and then ran it through webpagetest.org's visual comparison tool. I tested:

1. ajax.googleapis.com
2. code.jquery.com
3. ajax.aspnetcdn.com
4. cdnjs.cloudflare.com

Who was fastest: code.jquery.com by 0.1 second in both tests

Who was slowest: ajax.aspnetcdn.com by 0.7 seconds in first test and ajax.googleapis.com by 1 second in second test

Here's the 1st test (each was tested 3 times):

Video: http://www.webpagetest.org/video/view.php?id=121019_16c5e25eff2937f63cc1714ed1eac814794e62b3

Reports: http://www.webpagetest.org/video/compare.php?tests=121019_D2_KF0,121019_9Q_KF1,121019_WW_KF2,121019_9K_KF3

Here's the 2nd test (another 3 each):

Video: http://www.webpagetest.org/video/view.php?id=121019_a7b351f706cad2c25664fee7ef349371f17c4e74

Reports: http://www.webpagetest.org/video/compare.php?tests=121019_MP_KJN,121019_S6_KJP,121019_V9_KJQ,121019_VY_KJR

Answer 4

Google will send you a jQuery version minified with their own software, this version is 6kb lighter than the standard minified version served by MS. Go for Google.

Answer 5

One additional consideration - if your site is SSL and you need to support Android 2.1 (or earlier), the SSL certificate on the HTTPS version of the Microsoft CDN will crash those versions of the Android browser, per this issue: http://code.google.com/p/android/issues/detail?id=5001. It's not Microsoft's "fault", as the SSL certificate is technically valid and the defect is in Android's SSL implementation... but it will crash your site, nonetheless.

The SSL cert on Google's CDN does not fall afoul of this particular issue (relating to the certificate's "Certificate Subject Alt Name").

So, for SSL + Android 2.1 support, use the Google CDN.

Answer 6

One minor thing to consider is that both companies offer slightly different "extra" libraries:

• Microsoft is offering the JQuery validation library on their CDN, whereas Google is not (http://www.asp.net/ajaxlibrary/cdn.ashx)
• Google is offering the JQuery UI library on their CDN, whereas Microsoft is not (http://code.google.com/apis/ajaxlibs/documentation/)

Depending on your needs, this may be relevant.