> Sure, that fancy CDN might be faster at serving up stuff than your server but looking up a CDN's domain is costing one more DNS lookup
In theory, perhaps. Real-world tests show otherwise often enough. https://github.com/h5bp/html5-boilerplate/pull/1327#issuecomment-14927169 TR;DR Browsers are capped at ~8 connections/hostename, but can handle ~12-16 connections at once. & those CDNs may be faster then your shared hosting, which will offset the DNS lookup (if that is needed).
I agree that most scripts should be in the footer; jQuery animations I find in many WordPress templates are perfect examples. However, sometimes JavaScript is used to pull & display the main content, so top-loading is the only way to reduce content load-times. As I explained above, it MAY be faster to early-load a few scripts.
YMMV; you have great warnings Peter, but best suggestion is "test for your self" for optimal performance!
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> Sure, that fancy CDN might be faster at serving up stuff than your server but looking up a CDN's domain is costing one more DNS lookup
In theory, perhaps. Real-world tests show otherwise often enough.
https://github.com/h5bp/html5-boilerplate/pull/1327#issuecomment-14927169
TR;DR Browsers are capped at ~8 connections/hostename, but can handle ~12-16 connections at once. & those CDNs may be faster then your shared hosting, which will offset the DNS lookup (if that is needed).
I agree that most scripts should be in the footer; jQuery animations I find in many WordPress templates are perfect examples. However, sometimes JavaScript is used to pull & display the main content, so top-loading is the only way to reduce content load-times. As I explained above, it MAY be faster to early-load a few scripts.
YMMV; you have great warnings Peter, but best suggestion is "test for your self" for optimal performance!