Secondary protip: use a DNS prefetch for even faster 3rd party asset delivery.

<link rel="dns-prefetch" href="//cdnjs.cloudflare.com">

More at: http://html5boilerplate.com/docs/#DNS-Prefetching

If you're loading the javascript on the same page you're surely going to see no benefit at all right?

The browser can parallelize the DNS lookup, whereas running it serially and delaying the RTT for the asset will be much slower. So there is significant benefit to be had regardless. More: http://www.chromium.org/developers/design-documents/dns-pref...

Neat trick! Thanks!

protocol relative URLs awesome, but be aware, because this is only good for scripts and images. stylesheets on such links are downloaded twice in internet explorer (http://www.stevesouders.com/blog/2010/02/10/5a-missing-schem...)