If using a CDN, the refresh tax and initial tax should be negligible -- Google's jQuery has a 1-year expiration date; code.jquery.com has an expiration date in

If using a CDN, the refresh tax and initial tax should be negligible -- Google's jQuery has a 1-year expiration date; code.jquery.com has an expiration date in 2037. Browsers shouldn't be re-checking them unless an explicit "reload" is used. Yes, there's a constant tax for parsing, etc. But that can be better fixed by having browsers add general support for caching compiled versions of JavaScript libraries. This way, even sites that use less famous libraries (Dojo or AngularJS or whatever) can get the same benefits.