The merits of having access to large scale delivery infrastructures provided by Google and the possibility that the client will already have these asset cached are huge wins.
It was doubtful that the benefit would justify the expense.
As such, they are calculated risks with tradeoffs. CDNs are great, but for those minutes or hours that they go down a year, they can be super annoying. However, using this library provides you with the ability to load these assets asynchronously and in parallel based on the ordering provided.
However, if this was a mission critical site, I should not only have a simple configuration switch to fallback to local resources, but I should also test and simulate a CDN going down so I'm prepared when it inevitably happens. Major CDNs do occasionally experience outages and when that happens this means that potentially all the sites relying on that CDN go down too.
Unfortunately jQuery 1. Though this is a little bit of a pain I still feel that this is the best solution to deploy, even just for the super simple API for loading JS resources. This example uses jQuery for ease of explanation, as we can be confident at this stage that at least the local version is in effect.
Note the important escape characters within the document.