Update html5shim/shiv to 3.6.1, use a CDN

[semenko]

This commit:

• Switches html5shiv to a CloudFlare cdnjs (from Google Code, which sets a sad Cache-Control max-age of 3 minutes)
• Makes html5shiv protocol-relative (not sure where Issue Use protocol-relative URL for html5shim in examples #1706 went)
• Updates html5shiv from vpre3.6 to 3.6.1 which fixes a few minor bugs

New html5shiv home: https://github.com/aFarkas/html5shiv

Signed-off-by: Nick Semenkovich [email protected]

[mdo]

What are the implications of this new URL and super short cache vs. Google Code? I've never heard of CloudFlare until today.

The protocol was restored because we were running into issues with IE hanging completely with it. I know IE7-8 will load CSS twice if used with protocol-less links, but I don't recall if we had the same problem with the shiv.

[semenko]

• Looks like the double-loading issue is only for stylesheets (per http://www.stevesouders.com/blog/2010/02/10/5a-missing-schema-double-download/ and running his example through http://www.webpagetest.org/)
• I think the biggest implication is since the Google Code URL isn't a CDN (and probably isn't meant to be used like this) their cache TTL is 180 seconds, so IE 7 & 8 clients frequently have the shiv expire. It also doesn't support gzip. The CloudFlare CDN has a TTL of about a year and supports gzip, which should reduce load times.

I think it'd be useful to have (1) an updated shiv, (2) with a long TTL & gzip, (3) on a reliable CDN. This meets the first two, though not 100% convinced about the third.

[iki]

• cdnjs seems impressive, although I never used it in production (we serve all from google appengine)
  • https://github.com/cdnjs
  • https://www.cloudflare.com/network-map
• regarding protocol-less javascript source linking, we never had issues on a site used by IE8 users heavily
• in this case, you can easily avoid both uncertainties above and serve html5shiv.js locally from assets/js/ together with jquery.js and bootstrap-*.js ... furthermore, you'll most probably save the IE8- users one dns request to resolve cdnjs.com, see http://zoompf.com/2012/05/html5shiv-and-serving-content-from-code-repositories

[mdo]

Opted to include it locally after reading @iki's comment. Updated and ready to go in #6346. Thanks folks!